This photoelectic smoke detector from infapower is bsi approved and requires no wiring to install it is powered by a simple alkaline battery which is included and is secured to a wall by easy to use fixing screws also included the device includes a test function and low battery indicator as well as a extra loud 85 decibel alarm features bsi approved no wiring necessary alkaline battery and fixing screws included extra loud 85 decibel alarm test function and low battery indicator smoke