... cover material:brass size:3/8", 1/2", 3/4" good quality,best price . CE UL CSTBAT adiator plug ... size 1/4 3/8 1/2plug for radiator installation, with NBR O-RingHeating Line use Air Release Valve1. Working ... O ring sealing,6. Pipe thread connection G1/2, G3/4 BSP/ISO, NPT7. Application: heating line system, radiators8. Regular ... and do our best to serve you Radiator Accessory Air Release Valve