These are new made 260mm (10.236″) SMG spec. barrels from BWE Firearms. The Muzzle end has a three chamber compensator machined in to it. Comp helps to control recoil and muzzle flip for improved accuracy and more rounds on target in full auto fire. They are the only barrels currently on the market that are made to IMI prints. They are 1 in 10″ twist barrels that are machined then parkerized as called for on the IMI print.
All NFA rules apply. These barrels can only be legally used in a registered machine gun, registered Short Barrel Rifle (SBR) or a pistol. They can not be used in a standard carbine with a 16″ barrel unless you register your carbine with ATF NFA as a legal SBR.