Slime Pro Smart Tubes have the sealing power of our standard tubes minus the weight. They instantly and repeatedly seal punctures for up to 2 years! Instantly seals up to 1/8 (3mm) punctures Provides flat tire protection for up to 2 years Pre-filled with environmentally-friendly Slime tube sealant Presta Valve Provides flat tire protection for up to 2 years Pre-filled with environmentally-friendly Slime tube sealant Presta ValveSlime Pro Smart Tubes are pre-installed with Slime and provide maximum puncture protection. That means longer distances, faster times and no flat tyres.The Microfibers in Slime':s patented formula are carried by the escaping air to the puncture, where they build up to form a plug that stops air loss, sealing a tread area puncture up to 3mm.