A gas hose is a flexible tube that is intended for transporting gaseous substances. Houses such as these must comply with the various requirements that are set out in European norms and ISO standards. The key ones are that they are flexible, gastight, resistant to a certain pressure of the gaseous component, resistant to wear and ageing and with only a limited pressure loss. Gas hoses have numerous applications: air hoses for the breathing air for divers, transportation hoses for natural gas to gas-powered equipment, medical applications such as hoses for oxygen and anaesthetic gas, transport of air for ventilation or heating purposes, transport of compressed air to all kinds of equipment and in air brakes in lorries and trains, as well as transport of all kinds of gases in the industrial sector. A gas hose can in some situations also be used for transporting underpressure (vacuum): vacuum lines and vacuum cleaner hoses.