This is an annunciator plate with a piezo-type Mallory Sonalert® audible signal device and volume control. The volume control can also be used to turn the Sonalert off. Push button functions on the faceplate include: manual on, reset, and exit delay (see below for description of each). Matches any decor. Can adjust length of tone from 1/2 to 30 seconds USE WITH CF2C ONLY!!!