Designed specifically for aftermarket and retro-fit applications, the P4043ME is ideal for controlling up to three water valve actuators with any latching or momentary contactor (not provided) capable of providing 120 VAC or 240 VAC. In addition, the P4043ME can switch the thermostat on most heaters between pool and spa when the actuators change position. The P4043ME is ideal for those applications where only simple water valve control is required and can be triggered by any switching device you may provide (i.e. light switch, spring wound AUTO/OFF, wireless switch, relay, etc…). Installation is easy! Simply snap the P4043ME into any existing Intermatic enclosure that contains an available mechanism support bracket, hook up power to both the P4043ME and the trigger device, and plug in your 24 VAC water valve actuators behind the top door of the mechanism