Ideally all tubeless tires should be repaired from the inside/out. But in an emergency situation that's not always possible. That's when the Stop & Go - Tire Plugger can do what no other tire repair kit can. It allows for an 'on the spot' and 'on the wheel' repair to virtually any tubeless tire. And it seals the puncture on the inside. The Plugger is a spring-loaded gun that 'drives' the plug into the hole. The shaft of the plug expands under pressure to fill the puncture. The mushroom head of the plug seats on the inner wall allowing no air to escape. This insures maximum reliability from its' revolutionary design. This kit comes in a durable hard sided case that will last for many years to come. And it's easily stored - so you're always prepared. The kit contains the Plug Gun, Nozzle, Probe tool, T-Handle Reamer/Rasp Tool, Retractable Blade, (25) Rubber Mushroom Plugs that measure 5/16" in diameter x 3/4" in length, and detailed instructions.