Refurbished laser scanner assembly, for the HP Color LaserJet 4650, 4650N, 4650DN, 4650DTN, 4610, 4610N. (Not for use in the LaserJet 4600 series). You may need to replace a laser scanner if you are experiencing any of the following error codes on your LaserJet 4650 or 4610: Error 51.20, 51.21, 51.22, 51.23 . There is one laser scanner for each of the 4 colors. NOTE: This is considered a major repair. Please check out our installation instructions to be sure you want to attempt the install.