Sprockets, Roller Chain, Metric are available from SDP/SI, an ISO 9001 manufacturer of over 540 sprockets, roller chain sprockets, ladder chain sprockets, and hubless sprockets. SDP/SI can modify our standard catalog parts to your spec or produce completely custom components for you. SDP/SI uses state-of-the-art CNC production facilities. Modified standard catalog parts or custom components are possible as well.