O-ring in NBR,HNBR,EPDM,Silicone,Viton,etc Hardness:ShoreA60,7,80,90 ... ,green,yellow,blue,etc NSF,WRAS,TZW,W270,FDA ItemNBR O-ring DescriptionDescriptionWidely used in bathroom product, valve, faucet, machine, hydraumatic, pneumatic ... and PFOS commands. Partial meet PAHS,NP requirement.NBR,EPDM,FKM,ACM,IIR,Silicon rubber etc. are available.Material usage is based ...