A flexible gas hose for liquefied petroleum gas - propane or butane - built to ISO 3821 with a black oil-resistant synthetic rubber inner layer, in orange for identification. Available in 5mm to 13mm bores, cut from 1 metre up to a 100 metre full coil, and date stamped.

Orange is the standard identification colour for LPG hose, so a gas line cannot be confused with any other hose in a bundle or on a site. It is not cosmetic - being able to identify a gas line at a glance matters when several services run together.

Because LPG hose degrades with age even when it looks perfectly sound. The stamp tells you when it was made and therefore when it is due for replacement - commonly five years, but check the appliance manufacturer's requirement. No legible date means replace it now.

Rubber is more flexible and more durable, particularly in cold weather where PVC stiffens badly, and it copes far better with repeated coiling and handling. PVC is flame resistant, rated to 20 bar and cheaper for a static installation. For anything portable or used outdoors in winter, rubber.

It depends on your cylinder valve. A 21mm butane valve takes a 21mm clip-on regulator at 28mbar; a 27mm propane valve takes a 27mm clip-on at 37mbar; a threaded POL propane valve takes a screw-on at 37mbar. All to EN 16129, all with an 8mm nozzle to suit this hose.

Push it fully onto the regulator nozzle and appliance spigot, secure with proper gas hose clips at each end, then leak-test every joint with soapy water before use. Bubbles mean a leak. Never test with a flame, and never rely on a push fit alone.