This part lets you use the official Bambu Lab PTFE tube coupler with the swiveling PTFE holder your A1 comes with. Good for having a direct reverse bowden to your filament dryer.

Unscrew the original through the hole in the side of the PTFE holder, take the screw out, and replace the original holder with this model and you should be set. 

PTFE holder top mount used in images.