The ServoCity Dual-Bearing Timing Belt Idler Pulley (8mm REX™ Bore, 18.5mm OD, 9.5mm ID) features a polycarbonate pulley with dual 8mm REX™ bore bearings, designed to adjust the tension and direction of a timing belt. The pulley offers a smooth surface for the belt, with flanges ensuring secure operation. One bearing is flush with the pulley, while the other is recessed, allowing for varied offsets based on mounting direction. The bearings' inner races align to maintain smooth rotation under axial loads.