Update 2/14/2024: Added a version without a hole/mount on the top for the post.  Several folks mentioned they removed or didn't use that so here's a version without.

Rev. 2 of my A1 top mount cap with optional post or cable guide. I use both options, one to keep the black cable out of the way, and the second (the post) to keep my AMS Lite spool adapters handy.

The cable guide swivels (use M3 screws) so that it doesn't bind, but keeps the cable up and out of the way. There are two loops in the .3MF, use the longer (oblong) the other is there for whatever, but the oblong works best for the black cable on the A1.

It's designed to slide down over the top.  If you want it to be really snug (not the way I designed this model) then reduce the x, y, or both axis in your slicer of choice (aka Bambu Slicer, OrcaSlicer, etc.) by .2-.4mm until it's snug.  Please don't be that guy who doesn't ask me a question to see if there is a reason or a why I did it that way or an option to make it more snug before slamming the design and giving it 3 stars.  As many will tell you, I answer questions pretty quickly and try to offer whatever help I can.