Built with a sturdy, copper manganese alloy coated with coated with nickel Compatible with GHK GBB Series rifles Durable, rigidly weighted barrels minimize vibrations and consistently improves accuracy Air Track Inner Bore design reduces air dispersion to maintain BB stability as it travels out of the barrel Tight bore 6.03mm inner barrel for improved range and accuracy Hop-up bucking includedSpecifications: Brand Poseidon Build Nickel Plated Copper Inner Barrel Diameter 6.03mm Inner Barrel Length 275mm Compatibility Tokyo Marui and WE Tech GBB Series Rifles 1X Inner Barrel