Timing Belt Pulleys are available in the following types: - XL 1/5" pitch - L 3/8" pitch - HTD 3mm, 5mm, 8mm pitch - Custom Design Pulleys - Molded high strength, glass reinforced nylon - All nylon or with aluminum hubs - Strong, accurate, lightweight, quiet running - Single or double flange - Set screw(s) and keyway(s)