You won't have to fear flats when you ride on rocky and rugged trails with the Slime(R) Smart Tube Presta Valve Self-Healing 29" Bike Tube. Featuring Slime(R) sealant, this tube prevents flat tires by instantly and repeatedly sealing punctures up to 1/8". The tube is made with strong Butyl rubber and the sealant offers protection for up to two years. Easily inflate the tube with its Presta Valve and enjoy a worry-free adventure. Features: Mountain bike tube Delivers durable performance on rugged mountain trails Prevents flat tires, instantly and repeatedly seals punctures up to ?" Self-healing design provides protection for up to 2 years Material: Butyl rubber Size: 29" Valve type: Presta Valve length: 48mm Valve threaded: Fully threaded with locking nut and removable Presta core Weight: 242g