The C-TEC BF319 is a high quality double pole (switches both live and neutral supply) fire alarm control panel mains isolator keyswitch. It is ideal for use during routine maintenance on the fire alarm panel such as battery tests and replacement of the main PCB etc. The BF319 fits onto a standard UK 47mm flush or surface mount back box and comes supplied with 2 x M3.5 25mm fixing screws.