Applied for fastening the tapered bearing to the shafts with support (“backrest”) , where here the shaft should be threaded so that the nuts can push the sleeve against the bearing. They are sold independently and accessories (nut and washer) must be ordered separately.Material: Nodular BGFN 01, 02, 03 (base GGG50) , which is the option with the highest tensile strength. Specifications: Brand BGL MPN AHX 3122 ID - Inner Diameter 105mm OD - Outer Diameter 120mm Width 68mm Weight (kg) 0.68