The Roberto Bianci 'Professional Commando' watch features an all stainless steel case on a rugged black rubber strap with a tire tread pattern. This men's timepiece showcases a silver dial with red and black accents, and a tachymeter scale on the bezel. Case: Stainless steel Caseback: Stainless steel screw-down with four screws Bezel: Black stainless steel with tachymeter Dial: Silver with three chronograph subdials Hands: Silvertone with luminosity Second sweep Markers: Luminous square Subdials: Three chronograph Calendar: Square analog date display at 4 o'clock Strap: Black rubber with tire tread pattern Clasp: Tang buckle Crystal: Mineral Crown: Screw-down Movement: Swiss quartz Water resistance: 10 ATM/100 meters/330 feet Case measurements: 45 mm in diameter x 14 mm thick Strap measurements: 22 mm wide x 9 inches long Model number: 7026rbgun_silver Click here to view our Watch Sizing Guide . All measurements are approximate and may vary slightly from the listed dimensions. Men's watch bands can be sized to fit 7.5-inch to 8.5-inch wrists. This watch has a screw-down crown (knob) for setting the time. Screw-down crowns create a stronger seal against the case than a push-and-pull knob, giving the watch a greater water resistance factor. To unscrew the crown, grasp the knob and turn it counter-clockwise (towards you) a number of times until it releases. Then pull or push the crown into position to set the time, date, and other functions. To close the crown, press it against the case while turning in a clockwise direction.