The Wattstopper BZ-50 Series Power Pack provides 24 VDC operating voltage for occupancy and light level sensing. Each is capable of switching up to 20A electrical load. The Slave Pack is similar to the Power Pack but has no transformer power supply, only an isolated relay. Power and Slave Packs can be combined to switch almost any lighting or HVAC load controlled by occupancy or light sensor controls. They can also be used for low voltage switching.