Built with durable, brass alloy Designed to increase stability and accuracy This uniquely designed barrel creates a cushion of air surrounding the BB as it shoots our of barrel Compatible w/ Tokyo Marui VSR-10, JG BAR-10, FN-SPR, VFC M40A3 and other airsoft bolt action sniper riflesSpecifications: Brand Maple Leaf Build Brass, Metal Allow Inner Barrel Diameter 6.01mm Inner Barrel Length 510mm Compatibility Tokyo Marui VSR-10, JG BAR-10, FN-SPR, VFC M40A3 and Other Airsoft Bolt Action Sniper Rifles 1X Inner Barrel