Page port preamp/ expander - page port pre-amp/ expander- pre-amplifies low level audio to remote sites- provides virtually unlimited Expansion for any system (150 Valcom one-way speakers per vc-v-1094)- Master volume control for entire system or groups of remote speakers- isolates page port from speaker lines- output Impedance: 600Ohm- Power requirements: -24 VDC, 45 MA- weight: 1.1lbs- Dimensions: 4.44H x 2.75W x 2.88D- Valcom Power unit (-1)vcv1094a.