Guren barrels are made of precise carbon steel & processed with HV500 coating.
This plating reinforced the hardness of the surface. It’s better than stainless steel (from HV200 to 400).
Guren barrels have a crown cut at the end of the barrel.
Hop window length : 6.5mm
Inner Diameter: 6.03mm
Outer Diameter: 8.55mm