1. inner tube20"x3.0"/3.5" AV48 mm (76/89-406)) Heavy duty bicycle replacement inner tube, Compatible with 20 X 3.0 20 X 3.25 20 X 3.30 20 X 3.50 fat tire tubes 2. 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 . 3. 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. 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. Installation: 20"x3.0"/3.5" bicycle heavy duty replacement inner tube for easy installation and removal. Check the valve position to ensure that the installation direction is correct. 6. Package Includes: 2 pcs 20 X 3.0/3.50 AV33mm heavy duty bike tubes. 7. This heavy duty inner tube is compatible with the corresponding models of mountain bikes, road bikes, Cruiser bikes, electric bikes; At the same time, the increase in thickness can meet the needs of the longer driving range and load of the prevailing electric bicycles.