Suitable for car and bike tyres, these inflators are useful for quickly filling tyres on the go. Being small and light means you can always have one ready. It's also quite simple to use, just screw on the gas cartridge and push onto valve of tyre. The valve is control by a spring release - so can control the rate at which the gas comes out of the cartridge by pushing less/more firmly against the tyre rim. Screw threaded CO2 cartridges into the mini inflator/pump and push onto the tyre valve.