... 20/25/32mm 4.BS4568,BN50086 Standards Item:Black Enamel Extension RingMaterial:Malleable IronFinish:Hot-dipped galvanization,Electro galvanizing,Black EnamelSize ... 32mmTypes:1-way,2-way,3-way,4-wayBlack enamel extension rings,to BS4568 and EN50086 standards.Best quality and ... reasonable price.We can produce the black enamel extension rings according to your samples or drawings,also we can ...