PTProof Tested

Precision instrument showroom / Test log archive

The specification promised. The test record shows what happened.

Enter the instrument archive. Open a test dossier, inspect the survival record, and find the books, watches, optics and field tools connected to each Proof Tested episode.

#ad As an Amazon Associate I earn from qualifying purchases.

Enter the Flagship Field Kit
Original overhead illustration of an unbranded precision instrument, optical instrument and rugged field case on an obsidian test bench.
Instrument study, no manufacturer marks

Test dossier index

The complete Proof Tested archive

No. 04Watches

The Only Watch the U.S. Military Specified as Standard Issue

In 1981, Casio engineer Kikuo Ibe dropped a pocket watch he had been given by his father, and the broken mechanism started a two-year design programme to build a watch that would not break when dropped.

Survival record
drop resistantshock resistantfirst digital standard issue
Casio G Shock WatchUS .comUK .co.uk
Open technical log

G-Shock is a line of watches manufactured by Casio since 1983, designed to resist mechanical stress, shock and vibration. G-Shock stands for Gravitational Shock. G-Shock watches are designed to resist mechanical stress, shock and vibration with 200 metre water resistance on most models. G-Shock watches include chronograph, alarm, countdown timer and backlight on most models. Newer high-end G-Shock models include GPS, pressure and temperature sensors. Casio engineer Kikuo Ibe is credited with the original design of the line; the first G-Shock model was the DW-5000C released in 1983. G-Shock watches have been adopted by the U.S. military as standard issue.

Watch the test
No. 05Watches

The Only Watch That Brought Apollo 13 Home

NASA issued every Apollo astronaut an Omega Speedmaster, and the Apollo 13 crew still had theirs on their wrists when the mission lost its engine 55,000 miles from home and came back on the lunar module.

Survival record
spaceflight qualifiedpressure testeddocumented mission
Omega Speedmaster WatchUS .comUK .co.uk
Apollo 13 NASA Mission BookUS .comUK .co.uk
Open technical log

Apollo 13 launched on 11 April 1970 and splashed down safely in the South Pacific on 17 April 1970. Nine hours into the mission an oxygen tank exploded, disabling the service module's main engine and most of the command module's electrical power. The crew used the lunar module Aquarius as a lifeboat, and looped around the far side of the Moon before the free-return trajectory brought them home. NASA issued every Apollo astronaut a standard Omega Speedmaster as government property, and the Apollo 13 crew wore theirs through the flight and the splashdown. The Speedmaster gave the crew a mechanical chronograph for timing burns and the re-entry, working with no dependence on the spacecraft systems that were failing. NASA required a chronograph for crew timing and navigation, which is the function a hand-wound mechanical Speedmaster was chosen to provide.

Watch the test
No. 06Watches

The Only Private Watch Ever Worn on the Moon

On Apollo 15, the Speedmaster crystal popped off during the second lunar walk. Commander David Scott switched to his own Bulova Chronograph Model 88510/01, a prototype, never produced for sale.

Survival record
lunar wornpressure testeddocumented mission
Bulova Moonwatch Apollo 15 WatchUS .comUK .co.uk
Bulova Moonwatch History BookUS .comUK .co.uk
Open technical log

- N A S A i s s u e d e v e r y A p o l l o a s t r o n a u t a s t a n d a r d O m e g a S p e e d m a s t e r P r o f e s s i o n a l , g o v e r n m e n t p r o p e r t y . - D u r i n g A p o l l o 1 5 ' s s e c o n d l u n a r e x c u r s i o n , t h e c r y s t a l o n D a v i d S c o t t ' s i s s u e d S p e e d m a s t e r p o p p e d o f f . - F o r t h e t h i r d l u n a r w a l k , S c o t t u s e d h i s o w n B u l o v a C h r o n o g r a p h M o d e l 8 8 5 1 0 / 0 1 , g i v e n t o h i m b y B u l o v a a s a p r o t o t y p e . - T h e w a t c h s h o w s s i g n i f i c a n t w e a r f r o m e x p o s u r e o n t h e M o o n , s p l a s h d o w n , a n d r e c o v e r y . - A p o l l o 1 5 l a u n c h e d 2 6 J u l y 1 9 7 1 f r o m K e n n e d y L C - 3 9 A o n S a t u r n V S A - 5 1 0 ; l a n d e d a t H a d l e y - A p e n n i n e o n 3 0 J u l y 1 9 7 1 . - T h e B u l o v a C h r o n o g r a p h 8 8 5 1 0 / 0 1 i s t h e o n l y p r i v a t e l y o w n e d w a t c h t o h a v e b e e n w o r n o n t h e l u n a r s u r f a c e . - I t s o l d a t R R A u c t i o n i n B o s t o n i n O c t o b e r 2 0 1 5 f o r $ 1 . 6 2 5 m i l l i o n .

Watch the test
No. 07Watches

The Only Watch That Went 10,898 Meters Down on a Robot Arm

The Rolex Deepsea Challenge prototype was strapped to the manipulator arm of the DSV Deepsea Challenger and functioned precisely at 10,898 metres at the bottom of the Challenger Deep, and the 2022 commercial reference 126067 carries an official depth rating of 11,000 metres tested to 13,750 metres for the 25 percent ISO 6425 safety reserve.

Survival record
10,898 m depthrobotic arm testpressure tested
Rolex Deepsea Challenge WatchUS .comUK .co.uk
Rolex Deepsea Challenge BookUS .comUK .co.uk
Open technical log

On 26 March 2012, the DSV Deepsea Challenger carried a Rolex Oyster Perpetual Date Sea-Dweller DEEPSEA CHALLENGE prototype strapped to its manipulator arm to a depth of 10,898 metres. The experimental watch was designed to be waterproof up to 12,000 metres and featured a domed synthetic sapphire crystal 14.3 millimetres thick. James Cameron stated the watch was the reliable companion throughout the dive, visible on the sub's manipulator arm and working precisely at 10,898 metres down at the bottom of the Challenger Deep. In November 2022 Rolex introduced the commercial Deepsea Challenge reference 126067 with an official depth rating of 11,000 metres, tested to 13,750 metres for the 25 percent safety reserve required by the ISO 6425 divers' watches standard. The commercial watch case is grade 5 titanium alloy, 50.0 millimetres in diameter, 23.0 millimetres thick, with a domed crystal 9.5 millimetres thick, and the case and bracelet weigh 251 grams. The Deepsea models use Rolex's patented Ringlock system designed to provide a higher degree of pressure resistance.

Watch the test
No. 08Watches

The Only Watch That Came Back From 3,900 Feet Underwater

In 1967, Rolex released the Sea-Dweller, a dive watch depth-rated to 2000 feet (610 metres), with a helium escape valve patented in 1967 and developed in collaboration with COMEX (Compagnie Maritime d'Expertises). The Sea-Dweller Deepsea variant released in 2008 is depth-rated to 12,800 feet (3,900 metres), and the Sea-Dweller Deepsea Challenge released in 2022 is depth-rated to 36,090 feet (11,000 metres).

Survival record
1,000 m ratedhelium escape valveCOMEX collaboration
Rolex Sea-Dweller WatchUS .comUK .co.uk
Rolex Sea-Dweller History BookUS .comUK .co.uk
Open technical log

The Rolex Sea-Dweller is a line of diver's watches manufactured by Rolex with a depth rating of 1,220 metres. The Sea-Dweller Deepsea variant is depth rated to 3,900 metres (12,800 ft). The Sea-Dweller Deepsea Challenge variant is depth rated to 11,000 metres (36,090 ft), added in 2022. The helium escape valve was patented by Rolex in 1967. The Sea-Dweller was developed in collaboration with COMEX (Compagnie Maritime d'Expertises) for saturation diving. The Sea-Dweller is part of Rolex's Professional line.

Watch the test
No. 09Watches

The Only Watch SOG Paid Its Fighters for Taking Prisoners

MACV-SOG created a reward system that prioritized capturing enemy soldiers as a secondary objective by offering Seiko watches, cash bonuses, and R&R trips to team members. This incentive structure produced actionable intelligence on PAVN troop movements while remaining secret until the early 1980s.

Survival record
1964 issuemilitary provenancedocumented service
Seiko 6105 Captain Willard WatchUS .comUK .co.uk
Seiko 6105 Captain Willard BookUS .comUK .co.uk
Open technical log

Teams also received rewards including free R&R trips to Taiwan or Thailand aboard a SOG C-130 Blackbird, a $100 bonus for each American, and a new Seiko watch and cash to each indigenous member. No matter the team's primary mission, capturing enemy soldiers always remained the team's secondary mission when the opportunity presented itself due to valuable intelligence gained related to PAVN troop movements, size, and base locations. Beginning in 1966, SOG conducted prisoner snatch missions of PAVN soldiers behind enemy lines along the Ho Chi Minh Trail.

Watch the test
No. 10Watches

Grand Seiko Accuracy: The 44GS Design That Endures

Grand Seiko began in 1960 as Seiko's highest-grade domestic watch line, introduced in December 1960 by Suwa Seikosha with the hand-wound calibre 3180. Its design is associated with the angular case and dial conventions of the 1967 44GS and, since 2020, the related Evolution 9 design code.

Survival record
calibre 4420B1967 issue1968 chronometry prize
Grand Seiko 44GS WatchUS .comUK .co.uk
Grand Seiko History BookUS .comUK .co.uk
Open technical log

G r a n d S e i k o b e g a n i n 1 9 6 0 a s S e i k o ' s h i g h e s t - g r a d e d o m e s t i c w a t c h l i n e . I n 2 0 1 7 S e i k o b e g a n p r e s e n t i n g i t a s a s e p a r a t e b r a n d , r e m o v i n g t h e S e i k o n a m e f r o m n e w d i a l s w h i l e r e t a i n i n g t h e s a m e c o r p o r a t e o w n e r s h i p .

Watch the test
No. 11Watches

TAG Heuer Accuracy: The Oscillating Pinion That Endures

TAG Heuer's slogan is "Swiss Avant-Garde Since 1860", a line rooted in the 1860 founding of Heuer Watchmaking Inc. by Edouard Heuer in St-Imier, Switzerland. Heuer's patents included the first chronograph in 1882, the oscillating pinion in 1887, and the "Time of Trip" in 1911, the first dashboard chronograph.

Survival record
1887 oscillating pinionautomatic movement1860 founding
Tag Heuer Carrera Chronograph WatchUS .comUK .co.uk
Tag Heuer History BookUS .comUK .co.uk
Open technical log

I n 1 9 1 1 , H e u e r r e c e i v e d a p a t e n t f o r t h e " T i m e o f T r i p " , t h e f i r s t d a s h b o a r d c h r o n o g r a p h . T h e d e s i g n u s e d t w o l a r g e h a n d s f r o m t h e c e n t e r p i n i o n f o r t h e t i m e o f d a y a n d a s m a l l p a i r o f h a n d s a t t h e t w e l v e o ' c l o c k p o s i t i o n f o r t r i p d u r a t i o n u p t o t w e l v e h o u r s .

Watch the test
No. 12Cases, Knives & Field Gear

The Only Knife Switzerland Gives Every Soldier, From Private to Officer

The Swiss Army has issued the same Soldier Knife to every soldier regardless of rank since the nineteenth century. The supply chain evolved from initial German production to a dual domestic supplier system that eventually consolidated into a single manufacturer.

Survival record
folding blademilitary issuedocumented service
Victorinox Soldier KnifeUS .comUK .co.uk
Victorinox Soldier Knife BookUS .comUK .co.uk
Open technical log

Soldier Knives are issued to every recruit or member of the Swiss Armed Forces and the knives issued to officers have never differed from those issued to non-commissioned officers and privates. At that time no Swiss company had the necessary production capacity so the initial order for 15,000 knives was placed with the German knife manufacturer Wester & Co. of Solingen Germany and these knives were delivered in October 1891. On 26 April 2005 Victorinox acquired Wenger becoming the sole supplier of knives to the military of Switzerland.

Watch the test
No. 13Optics & Cameras

The Camera Company That Hid 1.7 Billion Dollars in Losses

Between 1990 and 2011, Olympus Corporation hid approximately $1.7 billion in losses on Japanese investments through a scheme called tobashi, using inflated fees on M&A advisory deals. British-born CEO Michael Woodford exposed the scheme in October 2011, two weeks after being promoted to CEO, and was ousted on 14 October 2011 by the same board that had appointed him.

Survival record
documented auditindustrial opticsarchival case
Olympus Scandal BookUS .comUK .co.uk
Olympus Accounting Fraud BookUS .comUK .co.uk
Open technical log

Olympus is a Japanese optical equipment manufacturer; the accounting fraud was exposed in 2011. British-born Michael Christopher Woodford was ousted as CEO on 14 October 2011. Woodford had been company president for six months and CEO for two weeks when he exposed the scheme. The tobashi loss-hiding arrangement had been running since the 1990s. The scheme hid approximately $1.7 billion in losses on Japanese investments.

Watch the test
No. 14Aircraft & Service Weapons

The Only Bomber That Dropped More Bombs Than Any Other

The Boeing B-17 Flying Fortress was developed in the mid-1930s for the United States Army Air Corps and dropped more bombs than any other aircraft during the Second World War. Its prototype Model 299 out performed two other entries in an Air Corps competition but crashed, losing the initial 200 bomber contract to the Douglas B-18 Bolo.

Survival record
longest-serving bomberdocumented servicewar record
Boeing B17 Flying Fortress BookUS .comUK .co.uk
B17 Flying Fortress Aviation History BookUS .comUK .co.uk
Air War Over Europe Bomber BookUS .comUK .co.uk
Wwii Usaaf Bomber Pilot Memoir BookUS .comUK .co.uk
Vintage Wwii Flight JacketUS .comUK .co.uk
Vintage Pilot Leather Flight HelmetUS .comUK .co.uk
Vintage Flak Parachute HarnessUS .comUK .co.uk
Vintage Aircraft Oxygen MaskUS .comUK .co.uk
Open technical log

The Boeing B-17 Flying Fortress is an American four-engined heavy bomber aircraft developed in the mid-1930s for the United States Army Air Corps. It was a fast and high-flying bomber used primarily in the European Theater of Operations. In a USAAC competition, Boeing's prototype Model 299 outperformed two other entries but crashed, losing the initial 200-bomber contract to the Douglas B-18 Bolo. Still, the Air Corps ordered 13 more B-17s for further evaluation, which were introduced into service in 1938. The aircraft went on to serve in every World War II combat zone, and by the time production ended in May 1945, 12,731 B-17s had been built by Boeing, Douglas, and Vega. Vega was a subsidiary of Lockheed. Of the roughly 1.5 million tons of bombs dropped on Nazi Germany and its occupied territories by Allied aircraft, over 640,000 tons (42.6%) were dropped from B-17s. It was a relatively fast, high-flying, long-range bomber, and it carried heavy defensive armament at the expense of bomb load. In the USAAC competition the Model 299 outperformed two other entries and crashed, which almost wiped out Boeing.

Watch the test
No. 15Aircraft & Service Weapons

346 People Killed by Software Boeing Already Knew Was Wrong

The Maneuvering Characteristics Augmentation System (MCAS) on the Boeing 737 MAX pushed the aircraft's nose down based on input from a single angle-of-attack sensor. Two crashes followed, Lion Air Flight 610 on 29 October 2018 (189 dead) and Ethiopian Airlines Flight 302 on 10 March 2019 (157 dead), before the worldwide fleet was grounded on 13 March 2019.

Survival record
flight control softwaretwo crashesgrounded worldwide
Boeing 737 MAX BookUS .comUK .co.uk
Boeing 737 MAX Aviation Safety BookUS .comUK .co.uk
Open technical log

The Boeing 737 MAX is the fourth generation of the Boeing 737, announced August 2011, first flight January 2016. The aircraft was certified by the FAA in March 2017. The aircraft incorporates CFM International LEAP engines, split-tip winglets, and a flight control system called MCAS (Maneuvering Characteristics Augmentation System). Two crashes followed entry into service: Lion Air 610 on 29 October 2018 (189 dead) and Ethiopian Airlines 302 on 10 March 2019 (157 dead). The aircraft was grounded worldwide in March 2019; the two crashes killed 346 people combined.

Watch the test
No. 16Aircraft & Service Weapons

The Only Rifle Still Being Made When Its Empire Fell

The Karabiner 98k was adopted on 21 June 1935 as the standard service rifle of the German Wehrmacht, chambered for the 7.92x57mm Mauser cartridge, and was one of the final developments in the long line of Mauser military rifles.

Survival record
98 years in servicemilitary issuedocumented service
Kar 98K Mauser Rifle BookUS .comUK .co.uk
Karabiner 98K Rifle History BookUS .comUK .co.uk
Open technical log

The Karabiner 98k is a bolt-action rifle chambered for the 7.92x57mm Mauser cartridge. It was adopted on 21 June 1935 as the standard service rifle by the German Wehrmacht. It was one of the final developments in the long line of Mauser military rifles. It served as the standard German rifle through the Second World War. After 1945, some countries that had used the rifle retained stocks for reserve and irregular forces. Licensed copies of the design remained in production in countries like Yugoslavia and Czechoslovakia into the early 1990s - an effective service life of nearly 60 years.

Watch the test

Continue the test series

Watch Proof Tested

This page sets no cookies and runs no analytics. The outbound Amazon links may set their own cookies, which Amazon controls. Nothing is tracked on this page.

Original editorial artwork only. Product links are affiliate search links, not scraped product pages. Prices can change on the store site.