Traceable® key-chain timer is easy to use; counts down, alarms, and functions as a stopwatch. One of the handiest timers ever designed- holds your keys or hooks onto your lab coat buttonhole. Four-digit LCD display always shows time remaining in hours and minutes. Program it in the countdown mode in minute increments from 20 hours to 1 minute. When zero is reached, an alarm sounds for 60 seconds, or it may be silenced manually. In the stopwatch mode, it times from 1 second to 20 minutes and then repeats itself. Also has a time-out feature in both up and down counting. Big-digit, display is easy to read. Three-button operation is fast and intuitive. Stopwatch operation takes just the press of a single button. Designed for rugged use. Quartz-crystal. To assure accuracy an individually serial-numbered Traceable® Certificate is provided from our ISO 17025 calibration laboratory accredited by A2LA. It indicates traceability to standards provided by NIST (National Institute of Standards and Technology). Key-chain timer has a rugged, chemical-resistant ABS case, and a 1-1/2-year, continuous-use, replaceable silver-oxide battery. Replacement battery Cat. No. 1039. Features: Key-cha-Inch. Size: 2 x 1-1/2 x 3/4-Inch. Timing Range: 20 Hours. Resolution: 1 Second. Accuracy: 0.0001. Maximum Time: 20 Hours. Channels: 1. Countdown/Countup: Down/Up. Digit Height: 1/3-Inch. Weight: 3/4oz. Control Company#: 5041.