safety valve (Standards: ISO2037, DIN, 3A, SMS, IDF) 1)Specification: 1/2"-6" 2)Material: SUS304,SUS316L Stainless Steel Safety Valve3)Working principle: Remote ... : Silicon rubber ,EPDM5)Three drive forms: Normally closed, normally opened and opened and closed by two air flues separately6)Application: Pharmacy, beer ...