We are a substantial supplier of hot and cold water fittings into the Uk and Scandivia. We currently are purchasing approximately 10 milion O rings of varying sizes (12 mm, 15mm, 22mm). At the present time we source these from a supplier in China who has not got the EN681 test certificate for their O Rings. Do you have such a EN681 certificate? Are you interested in supplying us O Rings?Michael MarkhamPlastic Fittings Technology Limited