The OMNITRONIC PA Vol Contr/Prog Select 45W mono bk is a flush-mounting, mono PA program selector and volume controller for 100 V audio systems or other signals. It selects between six signal sources and provides volume attenuation in 11 steps. The unit has a built-in 24 V emergency priority relay, screw plug connections, a black plastic front panel and knobs, and a rated power handling of 45 W RMS.