Features: Wireless heartbeat signal transmitted from chest band frequency at AM 5.3KHz. Time display with hour, minute, and second. Alarm clock function. Alarm sounds when heart rate exceeds upper and lower limit values (60–220). Timing function with maximum timekeeping of 23 hours, 59 minutes, 59 seconds, and 99 milliseconds. 12 or 24-hour display format. Backlight and noctilucent function. Keystroke tone. Waterproof up to 3 meters. Specifications: Chest transmitter strap size: 66–95 cm (elastic) Language: English Movement type: Electronic Waterproof depth: 3 meters Closure type: Buckle Case shape: Round Functions: Alarm clock, heart rate tracker, 24-hour format, world time Material: Rubber strap, steel case Color: Black Total size: 245 x 22 mm Dial size: 41 x 16 mm Package Includes: 1 x Watch 1 x English manual 1 x Chest transmitter strap Notes: The actual color of the item may vary slightly from the images shown due to factors such as monitor brightness and lighting conditions. Please allow slight variation in measurement data.