UM Series Ultra Compact Mixer-Amplifiers 100V 100V mixer-amplifiers with USB audio player, FM tuner and BT wireless receiver in an ultra compact housing. Microphone input, line input and USB/FM/BT sections are governed by front panel volume controls and a master volume. Mono output to either 100V line or 8 Ohms speaker load is connected via screw terminals on the rear panel. Supplied with hardware for mounting 2 units side by side in a 1U 19″ rack space. Designed as a versatile solution for small to medium PA installations.