Low pressure gas hoses have to comply with BS 3212 Type 1, which states that they must be orange or black and be secured with proper worm drive clips - round metal clamps which are smooth on the inside. They don't have to be reinforced to the same extent as high pressure hoses.
They are used for appliances that need a relatively low heat output such as camping stoves, patio heaters and caravan fridges.
Because low pressure hoses don't come with their own connectors, you need to be extra careful when fitting them. Always push the hose as far onto the barb, or spigot, of the regulator as it will go, and tighten the clip gently so that it fits securely but doesn't bite into the hose.