2Jewellery Perfect Watches, Synthetic sapphire crystal, sunray movement. Movement: CAL.3H45 Model: 1915 Drive mode: double mainspring drive Power reserve: 72 (hours) Vibration frequency: 28800 (times/hour) Winding method: manual winding Case diameter: 45-30mm Case Thickness: 11.9mm Strap width: 20-26mm Case Material: 316 stainless steel Strap Material: Rubber Waterproof depth: 5ATM Glass material: synthetic sapphire crystal Buckle style: Butterfly double snap Crown: Straight