An easy to use photoelectric smoke alarm that needs no battery maintenance during its 10 year lifespan. Simply engage the internal battery by releasing the pin on the base of the unit, fix to your desired surface and test on a regular basis. Once the detector nears the end of its 10 year life, a low battery indication alerts you to replace the unit. This model also has a hush feature to reduce the unit's sensitivity for a ten minute period when required.Battery[tab]CR123A DC3V Internal (not removeable)[br]Alarm output[tab]85dB @ 3m[br]Dimensions[tab]101 x 34mm[br]Weight[tab]116g[br]Static working current[tab]<2µA