Comus pra sa heavy duty aluminium housed blue proximity switches comus pra sa 001 this 400v acdc 05a heavy duty proximity switch is housed in a hermetically sealed blue powder coated aluminium housing that ensures high corrosion resistance and a long life suitable for industrial and commercial use in harsh environments for applications such as position sensing linear actuators security switching safety guardsdevices comus pra sa 001 no heavy duty aluminium blue proximity switch