The ServoCity 3mm HTD Pitch Set-Screw Pinion Timing Belt Pulley (6mm D-Bore, 18 Tooth) is engineered to fit a 6mm D-shaft, making it suitable for use with compatible gear motors. It accommodates a 15mm wide 3mm HTD timing belt and features integrated shims to prevent flange contact with bearing races, ensuring smooth operation. Constructed from clear anodized aluminum, this pulley is both lightweight and durable.