The OPB15 Power Base is a unique, patent-pending, 15 Amp power pack for low-voltage occupancy sensors packaged in a housing that forms the mounting base of these products. This allows for installations where only line-voltage circuitry is available while providing the full-line of Leviton low-voltage ceiling sensors to meet every application. The OPB15 Power Base provides all of the same features as the standard OSP Power Pack Series with a full rated 15 amp, zero cross relay with 24 VDC supply. The Power Base Adapter converts any Leviton low voltage ceiling occupancy sensor to a self-contained, line voltage unit, with 15 Amp, 120-277V load capacity. Converts any Leviton low-voltage ceiling sensor to line-voltage (Patent-Pending) Mounts to standard 2.125" deep x 4" octagon or 2.125" deep x 4" foursquare electrical boxes (foursquare box requires a two-gang mud ring) Simple installation Ideal for retrofit or new construction applications Self-contained transformer and relay Zero crossing circuitry provides increased durability