Action Army VSR-10 Cylinder Kit. Reinforced cylinder for heavy duty upgraded spring pressure. Fits Tokyo Marui VSR-10 sniper rifles, clone guns, JG BAR-10, etc.Kit includes the cylinder and cylinder head assembly.***Please note: The cylinder head and cylinder are custom threaded to work together in this kit only (it's a matched set). You cannot use an aftermarket cylinder head with this Action Army Cylinder. Only use the cylinder head this kit comes with. Even other Action Army heads will not work. The threads on the cylinder are not compatible with PDI, Laylax, etc. We've had complaints about this, so don't try to add a custom one.