Federal Signal’s AudioMaster® 310-MV is an industrial intercom that provides reliable two-way communications and superior sound quality. This unit has a rugged Type 4X housing and is UL Listed and CSA Certified. The AudioMaster 310-MV’s standard features include volume control, call button, balanced line output, dust- and water-tight housing, listen/talk switch, remote device activation and the ability to power another intercom at 24VDC.