Lug to Lug: 46.8 mm. Glass Material: Sapphire Crystal Case Material. Movement: Automatic winding Caliber: Genuine Seiko NH38 Jewels: 24 Vibration: 3 Hz (21,600 BPH) Power Reserve: 41 Hours Water Resistant: 20ATM (200 Meters) English Instruction Manual: Yes. Any problem please write to us at first time, we can try the best to resolve all issues and satisfy you. Our working time is 12:00AM to 10:00PM in Monday to Friday (Beijing time).