What this cover does for the FFC plug assembly
The 5017845009 is a Type Cover from the Molex 501784 series, designed as the strain-relief backshell for 0.5 mm pitch FFC plug assemblies. It is not a signal-carrying connector — its job is to clamp the FFC tail against the plug's contact beams and prevent pull-out during cable flex. With 50 positions, this cover aligns with the full width of a 50-conductor FFC, ensuring every contact beam is properly retained.
Mating compatibility — which plugs it fits
This cover is explicitly listed for use with the 501786 and 501864 series FFC plugs. If your BOM calls for either of those plug series, the 5017845009 is the correct cover half. The cover snaps onto the plug body after the FFC is inserted, locking the cable in place without additional hardware. No secondary latch or screw is needed.