This tourniquet is a true one-handed device proven to be 100% effective, completely occluded blood flow of an extremity in the event of a traumatic wound with significant hemorrhage. It utilizes a durable windlass system with a free-moving internal band providing true circumferential pressure to the extremity. Once adequately tightened, bleeding will cease and the windlass is locked into place. A hook and loop windlass retention strap is then applied, securing the windlass to maintain pressure during casualty evacuation.Please refer to the user instructions in the packaging for more details.