MIYOTA 8215 Automatic Mechanical Movement: When wearing a mechanical watch, the arm swing can drive the internal machinery of the watch, and the power storage can be up to 42 hours.21 JEWELS ? SS316L stainless steel strap Single fold push clasp: The buckle are strong, one-button opening and closing, Quick and easy to wear, full of texture Sapphire Crystal: The hardness is second only to diamond, and it is scratch resistant Rotating Ceramic Bezel Sealed Non-slip Crown:The Rotatable bezel counter is for accurate time calculation..The notch on bezel is designed for better rotation 100M WATERPROOF: It is available for daily hand washing,swimming, surfing or other water sports Always move, move forward without fear 100 Deep waterproof. 360 Rotating ceramic bezel.