... ring kits Features,1) Available material : material for NBR,FKM,FPM,VITON(FKM)&Dow elastomers,Neoprene,HNBR,Natural rubber,SBR ... ,IR,IIR(butyl rubber),ACM ect.NSF an KTW approved ... for sealing Our factory is a professional manufacturer of rubber products ,you can get much more information from ... a fruitful mutual business.. silicone o ring kits