... Sensitive 3.Long life and competitive Description : 1. The push button adopts zinc alloy body with anti-impact design , the surface ... .4. the locknut (regular type, super thin type )push button are installed into thickness 1.2mm to 3mm faceplate . 5 ... include : floor indictor, up/down , open door/close door , alarm ,telephone, emergency stop, emergency lighting , different indictor, key switch etc ...