electronic timers:
supply voltage:24~240Vm AC/DC
max current : 4mA

A timer is a specialized type of clock. A timer can be used to control the sequence of an event or process. Whereas a stopwatch counts upwards from zero for measuring elapsed time, a timer counts down from a specified time interval, like an hourglass. Timers can be mechanical, electromechanical, electronic (quartz), or even software as all modern computers include digital timers of one kind or another. When the set period expires some timers simply indicate so (e.g., by an audible signal), while others operate electrical switches, such as a time switch, which cuts electrical power.

drain valve:

Solenoid valve plus timmer

--YS-720: Analog and digital electronic interval timer

--YS-2000: Analog and digital electronic interval timer

--YS-11: Analog and digital electronic interval timer