This is a well tested spool adapter to allow use of a Protopasta 500G filament reel with a Bambu reusable spool. Changes from previoiusly avaible models are: 1- a “spiky” hub that engages the cardboard spool hub without slipping, 2- a slighly increased inner diameter of the adapter, there is no reason for the adapter to be tight on the Bambu spool--it has to go on easily and engage the notch, 3- an improved profile of the outer rim of the adapter, prevents filament from getting “hung” on the edge. Using this on the 500 G Protopasta spools involves--leaving the plastic wrap on the spool as it comes, carefully prying the cardboard flange off, and carefully cutting the glue off the inside of the hub, best to use a small wood chisel and not a razor to do this. Put the adapter on the Bambu reusable with the notch and insert. Repeat on the other side. Hope this helps.