This is Multi function led timer product,have real time clock, countdown, count up， stopwatch and Intervals counter functions, and very easy to operation. Digits height: 1.5 in(3.81mm). Color: 2 Digits Green & 4 Digits Red. Size:290mm(11.417 inch)*100mm(3.94inch)*40mm(1.575 inch) Time: HH: MM Format: 12 / 24H. 12H display format: H2 HH:MM 24H display format: H1 HH:MM Stopwatch: MM: SS: SS (1 / 10s) / (1/100 s) format - from 00:00:00 to 99:59:99 Count up (00:00 to 99:59)/ Display Format - [UP MM:SS] Count down (99:59 to 00:00)/ Display Format - [dn MM:SS] Stopwatch - (00:00:00 to 99:59:00) Display Format - [MM:SS:(1/10s)(1/100s)] Fitness Clock: Training rest alternately (editable training, rest time and cycles) F1 The first group training time F1 MM SS C1 The first group rest time C1MM SS F2 The second group training time F2 MM SS C2 The second group rest time C2 MM SS F3 F4 ------ F20 It can set up 20 groups of training and rest After the completion of the final alternately, It will rang three seconds sound,represents the entire training rest ended. When each timer is started the clockstarts a 10 second countdown and a beep on 3, 2, 1, Go! NOTE: This remote control does NOT have an internal battery CR2025 3V because battery do not allow to ship so please buy from your local market. When control distance close or can not control the led timer, change the IR remote control fresh CR2025 battery.