From Madbull, these are fully licensed Noveske style Aluminium outer barrels. Tough, light and high quality; Madbull makes some of the best outer barrels around and they offer them in a broad variety of lengths. A standard M16 has a 20 inch barrel while the standard M4A1 has a 14.5 inch barrel but the beauty of the M16 family is their ability to modify the length with a lot more options then that.
This 12.5 Inch (328mm) barrel is dubbed the 'Crusader' barrel. At only 2 inches shorter then the carbine length M4A1, both shooting and tactical performance remains identical for the most part. Broadly speaking, the difference is almost entirely aesthetic as a difference of 2 inches in this length range is fairly negligible (with AEGs).
This is a light grey colored barrel with a low profile black gas block and chrome silver gas tube.