Double anti-reflective treatment for better readability. All TAG Heuer watches are fitted with sapphire crystal. This is cut from a polished slice of solid sapphire that has been created by the fusion and crystallization of alumina. Sapphire is so hard that only a diamond can scratch it. Distinctive S-Link bracelet has a folding clasp with a security system to prevent accidental opening. TAG Heuer Automatic chronographs make it possible to measure times of up to 12 hours with an accuracy of 1/8th of a second. They are all fitted with very high-frequency Swiss movements and represent one of the great achievements in the long watchmaking tradition and history of the company. The principal characteristics of TAG Heuer automatic chronographs are reliability, simplicity of use and a highly legible display. They have a number of useful functions for professional and leisure sporting activities, as well as for everyday use: Simple time measurement & additional time measurement. Anti scratch curved sapphire crystal. Faceted polished rhodium plated minute and hour hands, with luminescent markers. Hand-applied curved, faceted and polished indexes. Oversized 9 o'clock sub-counter. Tachymeter scale on bezel for average speed measurement. The tachymeter indicates the average speed of a car, for example, by measuring the time taken to cover a given distance (a kilometer or a mile). Screw in crown with double gaskets. Polished steel crown with double gaskets. Polished steel push buttons. Hand applied monochrome TAG Heuer logo. Date window at 3 o'clock. Water resistant to 100 meters; ensured by rigorous manufacturing standards and strict testing. Screw fitting case back. The high level of TAG Heuer quality is founded on the rigorous choice and continuous monitoring of all its suppliers and their products. Throughout the manufacturing process, each component is subjected to numerous tests and controls designed to verify how carefully it has been made.