This is the next generation internal spool holder offering much greater refinement - if you're using the original threaded version, or one based on that design, you're probably going to want this one. Working with it is a much smoother process and it prints more cleanly without the threads.

This is an evolution of the spacer as originally conceived for the Centauri Carbon internal spool kit. This one is double the depth and has controllable vents to assist with keeping things cool for certain filament types.