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 ... . air vent valve:1. material:brass2. size: 1/2",3/4",3/8"3. manual air vent4.working pressure:3 bar5.working temperature: < 100 degree air vent valve