PP Compression Fittings for Irrigation 1. description1). Donsen compression fittings and clamp saddles are designed specifically for connecting polyethylene pipes with an outside diameter of 16-110mm (135 mm for clamp saddles).2). fully compatible with all PELD,PEHD,PE40,PE80 and PE100 pipes with external diameters of 15-34 mm.3). The Compression fittings allows the maximum working pressure (PN~ ...