Diving watch

The diving watch is a waterproof and pressure-resistant wristwatch (waterproof to at least 20 atm, corresponding to 190 m water depth). It is used to measure the dive time and is equipped with a rotating bezel to mark the start time of the dive. For safety reasons, the bezel can only be turned counterclockwise. Should it change unintentionally during the dive, the marked start time will always be before the actual start time, and there can therefore be no damage to health due to unintentional exceeding of the no-stop time.

Quartz

A quartz clock is a clock that uses an electronic oscillator that is regulated by a quartz crystal to keep time.

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Buckle

The pin buckle is a locking mechanism for bracelets. Holes are punched into one, longer part of the bracelet, at the end of the other is the actual buckle. The buckle itself consists of a pin that passes through the hole to fix the desired length, a spring bar and a U-shaped metal shackle that prevents the pin from slipping out of the hole again.

Sapphire glass

One application of synthetic sapphire is sapphire glass. Here glass is a layman term which refers not to the amorphous state, but to the transparency. Sapphire is not only highly transparent to wavelengths of light between 170 nm (UV) and 5300 nm (IR) (the human eye can discern wavelengths from about 380 nm to 750 nm[33]), but it is also five times stronger than glass and ranks a 9 on the Mohs Scale, and much tougher than tempered glass.

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