High quality fittings feature Multi Fittings special high molecular weight PVC compound with the highest impact strength currently available in North America. Our DR18 CIOD sewer fittings have a minimum DR18 thickness and are specifically designed for non-pressure sewer applications only. They feature the same water-tight gaskets as our AWWA C900 pressure fittings and can be equipped with oil resistant nitrile gaskets for use in soils that are (or potentially could be) contaminated with hydrocarbons.