Leak Gopher LGLPWLD Series 4000 Low Profile Wireless Leak Detector - 3.6/9V Battery
LGLPWLD
Powered by a 9-volt battery, it also can be powered by a 3.6-volt power adaptor (included). If it is being powered by the power adapter, and the 9-volt battery is installed, the battery serves as a battery backup.
The Series 4000 Low Profile Leak Detector