This barrel replaces the shorter stock barrel inside the PP750 shroud. The new barrel goes full length. It will give you better efficiency and more shots per fill. You can choose the 1/2×20 end cap to add a standard airgun silencer if you are in the USA or a muzzle brake in Canada.
Warning: if in Canada make sure and test your pistol to ensure it stays under the legal limit of 500fps after exchanging barrels. You can decrease velocity by turning the internal regulator at the base of the pressure tube clockwise a quarter to max half a turn. Velocity can also be decreased by turning the hammer spring adjuster at the back counter clockwise.