The HP A8P79-65015 Scanner Whole Unit Kit is a scanner assembly replacement part for supported HP LaserJet Pro MFP printers. The exact part number identifies the complete scanner unit kit, intended to replace the scanner assembly in a compatible device.
The listing identifies the part as an HP Inc. OEM item and names the LaserJet Pro MFP M521dn and M521dw as compatible models. This makes it a model-specific service part for restoring scanner functionality in those printers.