Sper Scientific 810041 Compact Visual and Audible Alarm Timer Sper Scientific 810041 Compact Visual and Audible Alarm Timer - 99 Hour Select either a bright flashing yellow LED visual alarm or an audible alarm. Built in stand for bench top use, clips to a pocket, with a magnetic back. Flashing yellow LED visual alarm or an audible alarm Count Up Channel: 0 Count Down Channel: 1 Range: 99 Hours 99 Minutes