This is a Maverick N-Strike Barrel Attachment Muzzle, which, once installed, allows N-Strike Style barrels to be attached to the Maverick. It replaces the existing muzzle, which can be removed after the blaster is taken apart.

This muzzle can be used on a stock Maverick but it is also compatible with my Mayfly Maverick Flywheel Conversion kit.

Esun PLA+ Orange was the filament used for the example part.

Links for all the parts used in the build shown:
Mayfly Kit: https://makerworld.com/en/models/255348
Maverick Stock Attachment Point and Slide Replacement: https://makerworld.com/en/models/255358