Spring-loaded small spool adapter for AMS Lite

This is a spool holder for spools with an internal diameter less than the 53 mm supported by AMS Lite. I have been using it with Sunlu 42 mm 250 g spools. Like the original Bambu holder, it retracts (using its 3D-printed spring!) the filament when the AMS Lite feeder pulls it back from the print head. This can help to avoid entanglement, especially with multi-colour printing involving lots of filament changes. Adjustable resistance: The force required to rotate the spool can be changed simply by screwing the cap on looser or tighter. The spool does not scrape along on the outer holder part, instead the whole adapter rotates, except for the little plug that goes in the hex or rectangle slot on the AMS Lite base. The screw cap controls the amount of friction between the plug and the rest of the adapter.Note: To avoid the cap getting loose, the hexagon cap has a reverse (left) thread, i.e. rotate it counter-clockwise to screw tighter! Model: 1 spool adapter requires 4 parts:The "outer