The detectors BS-655 were created to offer quickdetection in case of fire.They have two parts, one plastic base which isinstalled on the ceiling and the main unit of the detector which is fastened to the base by a simple turning to the right. The detectors have an indication led which lights continuously in case of fire detection until there is a reset signal from the panel. The indication led also flashes every 4 secto indicate good operation. These detectors can cooperate with conventional fire alarm panels like BS-632 and BS-636.