air vent valve 1.> material:brass 2.> size: 1/2",3/4",3/ ... TRV Co.,Ltd.specialized in the manufacture of thermostatic radiator valve.We have produced this kind of products for ten years ... ,Turkey, Poland, Ukraine, England, New Zealand and so on. air vent valve:1. material:brass2. size: 1/2",3/4",3/8 ... vent4.working pressure:3 bar5.working temperature: < 100 degree air vent valve