Loose flanges are used together with HDPE polyethylene adapters (flange ends) in water supply, sewerage, and natural gas installations. Loose flanges slide onto HDPE connection fittings and allow joining with valves or parts that connect with flanges. Material: carbon steel. Reference standard SR EN 1092-1 Flanges and their joints. Circular flanges for pipes, valves, fittings, and accessories, symbolized by PN. Part 1: Steel flanges. Steel loose flanges have standardized dimensions, except for the inner diameter, which is adapted to the size of the flange stub (Waterkit). Explanation of terms in the designation: D= outer diameter of the flange stub with which the flange is compatible. DN= nominal diameter of the flange according to SR EN 1092-1, SR EN ISO 6708. Compatible with: PE100 PN10 flange stubs, item codes 44417% and 45417%. Flat rubber gaskets, item codes 44799%. Set of bolts with nuts and galvanized washers, item codes 44798%.