Conbraco Industries 4A 203 A2F Preventer 30067439 890 Its durable construction ensures accurate Its durable construction ensures accurate discharge air temperature or return air sensing in high static environments NBR (SOX) remains the standard for general purpose industrial applications requiring balanced flexibility and oil resistance It is designed to replace the 4A 203 T2F while maintaining the same center line dimensions and port clearance for testing tools The Conbraco Industries 4A 203 A2F is a professional grade 1 2" bronze backflow preventer test cock designed for high precision field testing of reduced pressure zone (RPZ) and double check valve assemblies