The 24V 750mA transformer for indoor sprinkler controllers is a direct replacement for Orbit 24 VAC indoor controllers. The input is 110 VAC and the output is 24 VAC which is standard for pump relays and solenoids in North America. The 750mA capacity makes it capable of simultaneously powering two valve solenoids or one pump relay and one valve solenoid. If you need to install an indoor controller and transformer in an outdoor location, then we recommend installing it in the outdoor sprinkler controller cabinet. This transformer is compatible with 750mA max indoor controllers from Orbit, Hydro-Rain, and other major brands.