This is a suppressor remix based off the Titanfall Smart Pistol Mk5 from FusedCreations, to fit on the SBF. It has several ports in it to allow air for flow though it, and it's oversized to keep the dart from coming in contact with the walls of the faux suppressor.
The author remixed this model.
I remixed this with the muzzle from GavinFuzzy to make it fit on my SBF.