HP 6602-003644 is a belt-timing gear for printer equipment, identified by the distributor as an Original HP part. It is a replacement component for maintaining the printer assembly that uses this specific belt part.
The listing gives the designation B40S2M390,CR, which helps distinguish this belt from other timing gear belts in the same parts catalogue. The product reference is 6602-003644; the confirmed information describes it as a belt-timing gear and does not specify dimensions or package contents.