PUMP START REALY AUTOMATICALLY ACTIVATES WATER PUMP WHEN SPRINKLER TIMER ACTIVATES WORKS WITH A RESIDENTIAL STANDARD 24 VOLT SPRINKLER SYSTEM AEASY INSTALLATION HEAVY DUTY CASE -WEATHER RESISTANT EASILY MOUNTS TO INTERIOR OR EXTERIOR WALLS WORKS WITH 1 HP 110 VOLT PUMPS OR 2 HP 220 VOLT PUMPS- RELAY MAKES AND BREAKS BOTH POWER LEADS TO THE PUMP (DSPST) COMPATIBLE -WORKS WITH 24 VOLT SPRINKLER TIMERS (TIMER NUST BE PUMP CAPABLE)