6 x 0.6 oz (16 g) CO2 cylinders. Can be easily refilled with air using a separate regulator. Estimated about 700 x 23c for road bikes (varies depending on temperature condition) *CO2 cylinders will quickly cool and freeze when inflated. Do not touch the gas cylinder directly. Once opened, the cylinder will be used for use. Please note that it cannot be stored. Please use CO2 as a first aid during sudden punctures. If you have a floor pump, please remove the CO2 and replace the air to normal air pressure.