Manway & Manhole gaskets are available for all sizes of tank manways that we carry. All manway gaskets are designed to meet today's sanitary standards in the brewing industry. In general, EPDM and silicone gaskets are comparatively very similar, though silicone has a higher and wider temp range, while EPDM offers higher acidity resistance. FKM is Viton's® lower cost alternative while providing the same chemical properties, however, FKM is not FDA approved.Important Notice: Glacier Tanks, LLC manway & manhole gaskets are designed specifically for Glacier Tanks manways and manholes. They will NOT fit on manways or manholes made/sold by other manufacturers. If you do not own one of our manways or manholes, please do not purchase these gaskets.