The HD24 X-TRACER ADAPTER.68 is a must for suitable for all .68 barrels with a 22mm threaded end, such as the M17, Hammerhead Oneshot Barrels, Lion Claw Barrel users. With this adapter you can attach your 0,68 T4E X-TRACER to your marker with a 22x1 thread. With this revolutionary technology you can now achieve the ultimate result.