This listing is not a weapon, nor can it be modified in any way to be used as or with any weapon.
This listing is for the digital files used to 3D print (or CNC machine) an M4 barrel adapter for a standard airsoft Thompson AEG. The zip includes the STL and STEP files along with a PDF blueprint that might be necessary to include with the STEP files if you send the model out to be CNC machined. Minor modification to the outer barrel may be necessary for proper fit.
THIS IS NOT A PHYSICAL ITEM. YOU WILL NEED TO HAVE IT 3D PRINTED OR MACHINED FROM THE INCLUDED FILES TO USE IT.