HP RC4-6540-000CN is an inner door hinge for select HP Color LaserJet Enterprise printers. It is identified as an HP Inc part and is listed for the M681F, M682Z and M681DH models.
This hinge is a replacement component for the printer’s inner door assembly. The confirmed compatible models are HP Color LaserJet Enterprise Flow MFP M681F (J8A12A), HP Color LaserJet Enterprise Flow MFP M682Z (J8A17A) and HP Color LaserJet Enterprise MFP M681DH (J8A10A).