PDL 687M3A/M 16 amp rotary switch module for 600 series plates. Labelled "AUTO/OFF/MANUAL. 3 terminal. Ideal switch to control PIR sensors or devices that require a wired override. Fits all 600 series grid plates and all extra switch mountings on power points. Use a 3 core (red,white,blue) lighting cable to the sensor then wire the light normally - this great little mech takes care of all the switching to make operating the sensor very simple.