Slime Self Sealing Tube 27.5x1.9-2.125‘’ Presta Valve 32mmSlime Self Sealing Smart Bike Tube 27.5x1.9-2.125. Self-Sealing Smart Bike Tubes with SLIME Inside. All SLIME Smart Tubes are factory-filled with a precise volume of SLIME Tube Sealant. Smart Tubes instantly seek out and seal punctures as they occur, preventing flats, repeatedly and continuously for up to two years. Ride without worries.716281507656