... Description : 1. The push button adopts zinc alloy body with anti-impact design , the surface processing can be customizes by ... different electroplated.2. According with standard ISO4190, EN81,GB /T24477 3. the contact type : ... .2mm to 3mm faceplate . 5.The series include : floor indictor, up/down , open door/close door , alarm ,telephone, emergency stop, ...