This is an AMS spool adapter for Peakace brand filament. Peakace is great performing filament at almost half the price of others. Only problem is its narrow, shorter spools do not play well with the Bambu AMS system. This spool adapter is a custom fit onto the outside of the spool to give it better traction on the AMS drive wheels. It provides extra height as well to help keep the filament from jumping theedge of the spool during rewind. The inside of the spool is designed to accept the K2-Kevin Spool Weight for Bambu AMS (https://makerworld.com/en/models/81622#profileId-86911)