SC-40A Air switch pressure switch,air pressure switch,air compressor ... ,differential pressure switch,water pump pressure switch SC-40 can be used together with SC-41 air button (also called as Actuator ... push on the air button will release the air switch. Model SC-40 Media Air or other non hazardous gas, water Operating ... ,1/4 NPT male thread, 1/8 NPT male thread SC-40A Air switch