A pocket size timer with four count-down channels each channel can be set from one second to 100 hours. One channel can be used as a count-up channel for the same time period. In the CLOCK mode hours, minutes and seconds are displayed with an AM/PM indicator, 12 or 24 hour modes may be chosen. Measures 2-3/4 x 2-1/2 x 5/8". Pocket clip magnet and button cell battery are included.. Certificate indicating traceability to NIST Standards.