Hamilton H42535140 Jazzmaster Auto 40mmTradition meets innovation in the Jazzmaster Automatic 40mm. Roman numerals on the dial add distinct style and our H-10 movement with its anti-magnetic NivachronTM balance spring guarantees precise accuracy. Anything is possible with this high quality timepiece offered with a variety of dial and strap combinations.JAZZMASTERStriking a perfect balance between tradition and sophistication, the Jazzmaster collection offers wearers the ideal timepiece for milestone moments, and beyond.SELF-WINDINGWrist movements cause the inner rotor to swing, transferring energy to the mainspring, and powering your timepiece. STAINLESS STEEL CASEA highly resistant alloy composed of steel and chromium. It can be worked to resemble a precious metal. It is nearly impervious to rust, tarnish, and corrosion. SAPPHIRE CRYSTALSynthetic sapphire crystal is a tough scratch-resistant material, only diamonds could leave a mark. H-10 CALIBERA three-hand automatic movement boasting a superior power reserve of 80 hours and featuring a Nivachron™ balance spring.WATER RESISTANCEYour timepiece is resistant up to 5 bar (50m) / 73 psi (164 ft).