Custom Products Combat Classic .693 20" Barrel Autococker Pants & Slide Shorts and also serves the purpose About Fuzion and also serves the purpose of allowing the user to pre mix silicon oil into the propane ensuring longer life of the airsoft replica in use The TECHT MRT Bolt for the Etha makes a great shooting gun even better by making it more efficient The entire barrel has been "fluted" and has superior porting to reduce noise and improve accuracy The Combat Classic Barrel is machined and honed to the same exacting standards as the Combat Pro System but does not have the interchangeable tip or optional hand guard thread adapter