Anti-scratch sapphire crystal with double anti-reflection treatment. All our 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. Plished faceted hands and indexes are hand applied and coated with luminescent material for enhanced visibility. Safety push button on the bracelet for comfortable use, prevents accidental opening. C.O.S.C. Chronometer for ultimate precision certified by the Swiss Office of Chronometry. Each model that is officially certified as a chronometer is given a booklet and a C.O.S.C. card by TAG Heuer. The individual number printed on the card corresponds to the number engraved on the movement certified by the Official Swiss Chronometer Control. Each of these movements is a unique object that has been produced with the greatest possible care and is an authentic masterpiece of watchmaking. The C.O.S.C. Chronometer Certificate: a sign of very high precision and quality. Tachymeter scale on bezel fro 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). Water resistant to to 100 meters ensured by rigorous manufacturing standards and strict testing. Oversized screw-in crown - easy to hold and with two security gaskets reliable to 100 meters. Large date display at 6 o'clock. Double sapphire crystal casebook fitted with six screws reveals movement. Permanent seconds at 3 o'clock appears in a Rotating System decorated with "Cotes de Geneve". Exclusive TAG Heuer rotating system with "Cotes de Geneve" finish.