STOP Flats Ride Flat Free! STOP Flats2 is a remarkable tire liner made of durable, lightweight polyurethane. When inserted between the bike tire and tube, it provides a protective layer between road hazards and the inner tube. Thorns or glass that may penetrate the tire are blocked from the inner tube. Proven Tough - For over two decades we have been the world's leading tire liner maker with Millions upon Millions of satisfied cyclists. Economical - STOP Flats is our economy lire Liner. It has I layer of protection. New, Improved! - Now there are two STOP Flats. The original single ply and the new 2 ply STOP Flats2. Twice as Strong! (see side bar) Lightweight - Weighs less than liquid fills and thorn-resistant tubes. Recyclable - Use from bike to bike. Adds Bike Safety - Gives bicycle a smooth, stable ride. Easy installation- No gooey mess. Absolutely, Positively - Will not cause tire or tube damage-or loosen spokes Guaranteed! -STOP Flats and the new STOP Flats2 both comes with a FREE INNER TUBE guarantee.If you get a flat tire while using STOP Flats, or the new STOP FIats2, just return the damaged innertube and tire liner to us and we'll send you a brand new innertube and tire liner. See GUARANTEE for complete details. All Sizes - STOP Flat2 Tire Liners are available to fit almost any size tire.