The ServoCity 2mm Pitch GT2 Pinion Timing Pulley (5mm Bore, 20 Tooth) is designed for high-precision applications such as printers, sliders, and XY tables. It features a dual-material construction with a steel flange and barrel for durability, while the rest of the pulley is made of lightweight aluminum. This pulley is compatible with 5mm diameter shafts, commonly used in NEMA 17 stepper motors, and includes built-in shims to prevent contact with bearing races.