1. inner tube:20"x4.0"/4.5" AV32mm (102/114-406) Heavy duty bicycle replacement inner tube, these inner tubes are ideal for a wide range of applications. Enhanced the ductility of the heavy load tire, so that the scope of application is expanded, Compatible with 20x4.0 20x4 1/4 20x4.25 20x4.5 tires. 2. Easy To USE :The Self Sealing Bike Inner Tube is a self-repair for some small holes or very fine cracks.For example, after a long time, some places will leak air quietly,accidentally hit nails and other problems, which are easy to repair.It is worth noting that our self-repairing inner tube can be used within the normal temperature environment and cold days -15 ℃,and it is more conducive to travel in cold weather. 3. Safe Bike Tires:Pre-installed with Sealant to provide maximum puncture protection and prevent flat tires on your bike.The self-repairing inner tube is a thicker design, which is more durable than the normal inner tower.The bicycle inner tube rolls through the tire repair liquid to automatically fill the punctured area.After testing, the leak can be repaired within 5~8 seconds under normal conditions. 4. Excellent shock absorption ability The heavy, strong, highly durable butyl rubber made from these inner tubes is a shock absorber to reduce vibration and eliminate the shock caused by bumps and rough surfaces on the road or pavement. butyl rubber for maximum ride comfort - upgrade your ride experience 5. Our heavy duty inner tubes have higher puncture resistance than ordinary inner tubes, and the thicker body can withstand more friction and wear, thus extending the life of the tube, reducing replacement frequency and maintenance costs. And in long-term use. 6. HEAVY DUTY - Air Tightness: Using high elasticity and butyl rubber and EPDM rubber, the thickness is increased by 40%, and the air tightness of the inner tube is increased by 200% than that of the ordinary butyl inner tube; After inflation, the tire can maintain a higher air pressure for 6-9 months, greatly reducing the inflation frequency. Good air tightness helps keep tire pressure stable, thus improving driving .