Guren 03-1 GBB Inner Barrel - 6.03mm - 90mm

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).

Hop window length : 5.5mm
Inner Diameter: 6.03mm
Outer Diameter:  8.55mm