Vittoria Pit Stop is a pressurized cylinder filled with compressed gas and polymer foam sealant. You carry the cylinder with you in a bike bag or jersey pocket. When you have a flat tire you simply open your valve stem, press the nozzle on the Vittoria Pit Stop canister onto your valve stem and press toward the tire to release the compressed gas and the liquid foam sealant. Both substances shoot into the tire under pressure. The gas inflates the tire while the foam sealant flows into the puncture and instantly dries, sealing the hole and fixing the flat. If you are familiar with the automotive version of this called "Fix A Flat" then you get the idea. It seals the hole and inflates the tire simultaneously.
