I had to repair an optical sensor on my Da Vinci Jr by replacing the IR emitter and detector (the LED was blown). I purchased your standard garden variety optical endstops from Amazon, but the connector was oriented a different way, the components were too close together and it was generally not compatible with the endstop on the Jr.

So I simply desoldered and removed the components and swapped them out, but the components have a larger form factor than the stock Da Vinci Jr endstop. The stock clip that both shields the components and clips the endstop into the chassis did not have a large enough clearance for the new parts, and it also is open on the front and back, leaving the emitter and detector unshielded.

This part is meant to replace the stock clip, while fitting the larger components that I soldered into the original board. I'm still tweaking some things to get it to clip in correctly. Most recently I extended the clip legs by 0.5mm.