Louroe Audio Monitoring ALA-4 is a four zone alarming base station designed to provide sound activated audio monitoring, when interfaced with Louroe microphones. Each zone has a variable threshold level (set by installer or owner) based on frequency and sound pressure that activates when a sound exceeds the set threshold level. A short alarm and lighted LED identifies the zone, along with a relay contact for activating a camera or other annunciation. Model ALA-4 is rack mountable. Compatible with all Louroe microphones. For one-way listen (no talkback). Dimensions: 19 inch W x 5 1/4 inch H x 9 1/2 inch D