Conform to ASTM D 2609 Full Assortment of Configurations and Adapters Clamp-Free Spiral Barb Irrigation Hose Insert Adapters NSF Certified for Use with Potable Water Engineered to provide positive grip and ease of installation. High quality and reliability have made Spears® insert fittings the preferred choice for irrigation and O.E.M. applications. A wide variety of PVC insert configurations and adapters are available for use with polyethylene pipe sizes 1/2? through 4?, plus 6? & 8? Couplings and Adapters for lay-flat type irrigation hose. Special 3/8? barbed configurations allow clamp-free connection to 1/2? I.D. polyethylene irrigation hose.