They're decent barrels actually. Very quiet to shoot. I like the longer control bore since it does give you more efficiency according to the testing I did back in the day. It's not a game changer but every bit helps. If it matches your gun, all the better.
Etek 3LT grey/black f/s
Valken Proton greyish/black f/s
68 4500 PE stubby, LP output f/s
68 4500 AIR tank(no reg) f/s
Creed Battery, eyes and noid f/s