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, designated by PN. Part 1: Steel flanges. Loose steel flanges have standardized dimensions, except for the inner diameter, which is adapted to the size of the flange stub end (Waterkit). Explanation of terms in the designation: D = outer diameter of the flange stub end 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 stub ends, item codes 44417% and 45417%. Flat rubber gaskets, item code 44799%. Set of bolts with nuts and galvanized washers, item code 44798%.