This is a PTFE guide mount that works with my bottom mount side spool holder as well as can be used universally for other side spool holders / dry boxes. It mounts to the original aux spool holder mounting holes on the back of the printer. the original m3x8 screws can be used. The mounts accepts a PT4-10 PTFE connector. I did add a extra hole in case you want to push a ptfe tube in directly without threaded connector.