Built with a sturdy, copper manganese alloy coated with coated with nickel Compatible with Tokyo Marui and WE Tech GBB series pistols 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 Precision 6.05mm inner barrel In the Box 1X Inner Barrel Specifications: Brand Poseidon Build Nickel Plated Copper Inner Barrel Diameter 6.05mm Inner Barrel Length 113mm Compatibility Tokyo Marui and WE Tech GBB series pistols California Proposition 65 Warning: Cancer and Reproductive Harm - www.P65Warnings.ca.gov