We're not afraid to say it-our Airlock Presta Valve Tubes are the best performing, self-sealing bicycle tubes available on the market. That's because they feature our powerful Airlock sealant that coats the tube for permanent protection against punctures. Not only this, but the sealant is designed to work continuously in order to prevent slow leaks from occurring, so erring complete catastrophe, you won't have to worry about flatting when you're riding over debris. We even addressed the common issue of sealant pooling with a completely homogenous design, so the tire/tube combo will always roll smooth and even. Features: Airlock sealant for greater protection. Non-toxic, non-separating formula. Works continuously to prevent slow leaks. Homogenous design prevents puddles.