No more flats Slime's Prevent and Repair Tire Sealant seeks out and instantly seals tread area punctures in tubeless tires up to 1/4" (6 mm). When a puncture occurs, our patented sealant is carried directly to the source. The pressure of the escaping air forces the particles into the opening, where they build up and intertwine to form a long-lasting, flexible plug. Instantly, air loss is blocked and a flat tire is prevented.