Sport Direct 20" Butyl Tube Set x 2 Inc Self Seal Repair Kit, Low Puncture resistance Aero Sport® 20" tube set: 100% butyl high quality inner tubes 2 x 20" with schrader valves, butyl rubber dominates the market and is used for almost all tubeless tires and quality superior bike tubes as its permeability to air is incredibly low - butyl tubes have only 10 percent of the leakage rates of natural rubber tubes. This means you spend more time riding and less time blowing up your tyres! Aero Sport® Ride On Air™ Depth: 80 MM Height: 110 MM Width: 100 MM Cycle Accessories Type: Inner Tubes 2 x 20" 100% Butyl High Quality Inner Tubes, Schrader Valves 1 Self Seal Repair Kit consisting of 6 Patches, Crayon and an Abrasive Pad