InnerThis is a very high quality tight bore barrel made from stainless steel.
Although expensive you know you will be getting a long lasting barrel made to very high tolerances.
Because of the strength and highly polished finish of the steel it is very resistant to scratches and dirt.
Also its nearly impossible to bend this barrel by accident, in guns with front ends with movement a brass barrel or worse an aluminium barrel will bend as you bend the outer barrel of a gun.
These are all facts which are often overlooked as players focus solely on price or how tight the bore is.
Speaking of tighter bore, this is a 6.03 bore which will increase the FPS of your gun.
Some players use this as one of many tuning tools for a quick 5 - 10 FPS bump for there gun.
The hop window isn't as wide as some, so if your looking to install one of the more modern style hop rubbers like a firefly or prometheus flat rubber system you may want to consider filling this window wider before installation, or after installation check to see if all the hop rubber is coming down correctly into the barrel.
Over all a fantastic quality product.
Fitments include -
Tokyo Marui - SGR12
M4 CQB-R NGRS Series
416 NGRS Series
And Others

Prometheus

Prometheus 6.03mm EG Inner Barrel - 275.5mm 416D Next Gen