Timer or wave-maker.
The Power Center is an easy-to-use, 24-hour timer that has 4 constant-power outlets and 4 timer-controlled outlets. The mechanical timer can set the time-controlled outlets to a minimum of 15 minute intervals, making it great for use with water pumps to create tidal-flow currents.
Unit includes a 3' heavy duty power cord and a 3-prong grounded plug. UL-Listed. Measures 12.5" L x 10.5" W x 9.5" H, maximum 15 amps @115V/50 Hz.