Model & MovementMovement: 8310 AutomaticPowered by the release of a wound spring, mechanical movements never require a battery. Automatic mechanical movements have an oscillating weight that winds the spring with the motion of the wearers arm.Band & ClaspBand Type: Stainless Steel BraceletClasp: Deployant Clasp with Push ButtonsCase & DimensionsCase Width: 37mmCase Material: Gold-Tone Stainless SteelWater Resistance: WR50/5Bar/166ft [Still Water Swimming]CrystalMaterial: Sapphire CrystalSuperior scratch resistance and hardnessDial & DetailsDial: Silver-ToneDetails: MetalMovement Functions3 Hand with DateAutomaticHack Feature60 Hour Power Reserve