The GEMC-WL-GB is an advanced Commercial/Residential wireless acoustic glass-break detector designed for use with Napco's GEM Series receivers and GEMC-RECV wireless receivers. To validate minimum RF signal strength during installation, see receiver installation instructions. For greater false-alarm immunity, the glass break sensitivity can be adjusted and customized to match the acoustics of the room. The detector is powered by a type DL123A or CR123A 3-volt lithium battery (provided) that will power the transmitter for up to 5 years. When battery voltage drops below normal, a low battery report will be sent to the receiver.