Containing both a 24 VDC supply and a 20 A line voltage relay for most models, the Leviton compact power pack provides low voltage power and line voltage control for Leviton occupancy sensors. Versions include auto-on and manual-on inputs for occupancy sensors, hold-on and hold-off capabilities, and a local input for momentary or maintained dry contact switches. The OSP power pack series is also used to supply power to the OSA Add-A-Relay model. The power pack conveniently mounts in a knockout hole of a standard junction box. The unit can be placed inside or outside the junction box with a simple twist-on nut. The internal relay can control up to 20 Amps at either 120, 230, or 277 VAC ballast load, 15 A for 347 VAC ballast load. Power supply for all OS series occupancy sensors and Add-A-Relay Switches incandescent, magnetic and electronic fluorescent, magnetic and electronic low-voltage and motor loads Compact size and light weight allows easy mounting through knockout in junction box (from either inside or outside junction box) with a simple twist-on nut. Unit is also approved for mounting in ballast channel cavity Single or multiple luminaire control from one or more sensors Companion Add-A-Relay provides additional load capacity