This is a filter holder for the air exhaust of the Creality Sermoon V1. It holds 1/4 of a Hikary carbon activated filter so you can print ABS without suffocating or something. You need double sided tape to atatch it to the printer. You need a filter in the air intake too so the fumes doesn't escape there. I made one but the design is not goog so I'm not posting at this time.