This is a comically fast print (< 1 minute print time on a Bambu P1S with all the speeds turned down) that replaces a tiny little plastic part that is otherwise impossible to find.
The Lightspeed Zulu 3, Zulu 2, and Sierra headsets all have these plastic volume slider tabs that insert into the rectangular slider itself. If one (or both) of yours has popped out, nowhere to be found, print this at 100% infill and glue it into place with a tiny dab of CA glue or similar, and you're good to go again!
(Just don't use acetone on the control box like I did to try to clean it up – isopropyl should work better. Acetone mars the surface finish.)
The author marked this model as their own original creation.