The power can be turned off and the clock does not need to be reset. Time calendar function: display year, month, day, hour, minute, second, week, 12/24 hour system optional. You can view the fastest, slowest, and average values. When you search for memory data, you can check it up and down. Each function is easy to use. Key mute function: It can be muted to meet the quiet link. The stopwatch 3 lines display, segmented storage, accurate value up to 1 / 100 seconds, the longest time is 9 hours 59 minutes 59 seconds. With statistical countdown function and number of functions, quickly turn the alarm on/off. The beat frequency can be selected 5 times / minute - 320 times / minute (5 times a few times) and has a timing function. 810 : record 10 result, 830 :record 30 result, 860 :record 60 result, 8100 :record 100 result Specification: Type: Stopwatch Timer Powered by: 1 CR2032 (include) Material: ABS Applications: Sports meeting, physical examination, track and field training Features: Stopwatch, 3 lines display, Accurate, Alarm, Field training supplies Dimension: app.7.5x6.2x2.1cm/2.95x2.44x0.83in Color: Black, White (optional) Quantity: 1 Pc Package includes: 1 Pc x Stopwatch Timer