Single channel timer has three key operation for ease of use. timing capacity: 99 minutes: 59 seconds count direction: up/down last time set memory audible alarm; displays elapsed time after countdown mounting options: lay flat on bench, stand on edge for vertical view, magnetic back for metal surface attachment requires one aaa battery included features a certificate of calibration and individual serial number, these electronic timers are tested and calibrated in h-b’s exclusive triple accredited/registered iso/iec 17025:2017, a2la accredited laboratory cert #2448.01, against equipment whose calibration is traceable to nist. cemarked, rohs compliant