The large-bore hose connecting a vehicle's filler neck to the fuel tank. It is much larger than a fuel line - ours are 38mm, 51mm and 57mm - and it has a steel wire helix in the wall so it will not collapse or kink as it curves round the bodywork.

An NBR nitrile rubber inner tube for fuel resistance, a spiral steel wire helix for crush and kink resistance, and a tough CR chloroprene rubber outer layer for weathering and abrasion. It is built to SAE J30 R6 and has a wrapped finish.

38mm, 51mm and 57mm internal diameter, in 0.25, 0.5, 0.75 and 1 metre lengths. Measure the outside diameter of the filler neck and tank spigot and match to the hose bore. Buy a little longer than you think - trimming is easy, coming up short is not.

Yes - the nitrile inner tube handles modern ethanol-blended petrol as well as diesel. That matters a great deal on older vehicles, where the original filler hose predates ethanol blending and is being attacked from the inside while looking passable from outside.

A fuel smell around the rear of the vehicle, fuel staining or damp on the underside near the tank, and difficulty filling without the pump cutting out repeatedly. If you can smell fuel after filling up, the filler hose is the first thing to check.

Because a filler hose has to curve round bodywork in a confined wheel arch, and a large-bore hose without support would kink at the tightest point. A kinked filler hose restricts filling badly - the pump keeps cutting out - and creates a stress point that eventually splits.