http://tinyurl.com/m7pgko4
Intermatic KM2ST-2G 2 Gang Toggle SPST 24-Hour Mechanical Timer
Two-gang, Toggle
Captive trippers are easy to set, cannot be lost
Tripper intervals are 20 minutes
72 trippers provide up to 36 ON/OFF events in 24 hour period
Three way, OFF/AUTO/ON override switch provides continuous ON or OFF positions