This is the thread protector designed for the Fixed Barrel Adapters that are used with the Liberty Mystic X suppressor. Should you choose to leave the mount on your rifle, now there is a thread protector to cover the threads while the suppressor is not deployed on the mount. This device is backwards compatible with the Mystic and Infiniti silencers as well. Back by popular demand, we have made them to where they give your carbine a cool look as well as protecting the threads! Get yours today!