Sentry SEN-R-R1 Receiver 1 channel. Voltage free contacts. Toggle/timed output. Receiver Rolling Code. Built in Power Supply: No. Supply Voltage: 12v DC. Lock Relay: Max 5A@12/24v AC/DC. No. Doors (Max): 1. No. Transmitters (Max): No limit. Compatible Readers: SEN-R-T1..