Compatible OPC drum haven't a metal gear. This gear should be remove from the original OPC drum with help a flat screwdriver and it uses in compatible OPC drum.
Also searched as:
Hewlett Packard (HP) LaserJet P 2055 / N / DN,P2055, LJ P 2055, LJ P2055, Laser Jet P2055, Laser JetP2055,
P2055D, LJ P 2055D, LJ P2055D, Laser Jet P2055D, Laser JetP2055D,
P2055DN, LJ P 2055DN, LJ P2055DN, Laser Jet P2055DN, Laser JetP2055DN,
HP2055