It depends on the gas and the cylinder valve, not on the appliance. Butane cylinders with a 21mm valve take a 21mm clip-on butane regulator at 28mbar. Propane cylinders with a 27mm valve take a 27mm clip-on propane regulator at 37mbar. Older propane cylinders with a threaded POL valve take a screw-on propane regulator at 37mbar. Check the valve on your cylinder before ordering - they are not interchangeable.

They deliver different pressures because the two gases behave differently. Butane runs at 28mbar, propane at 37mbar, and appliances are jetted for one or the other. Fitting the wrong regulator will make an appliance run badly and, more importantly, unsafely. Propane also works at much lower temperatures than butane, which is why it is the usual choice for outdoor and winter use.

EN 16129, which is the European standard covering pressure regulators for LPG. Buying to a recognised standard matters a great deal with gas equipment - the standard covers the relief mechanism, the materials and the pressure accuracy. We would strongly advise against uncertified regulators regardless of price.

The 21mm butane clip-on is rated at 1kg/h; the 27mm propane clip-on and the screw-on propane regulator are rated at 1.5kg/h. Check the total demand of your appliances against that figure - a regulator that cannot supply enough gas will cause an appliance to run weak or cut out under load, particularly on larger burners or when several are used at once.

The 21mm butane clip-on is rated 0C to +50C, the 27mm propane clip-on -10C to +65C, and the screw-on propane regulator -20C to +50C. This is another reason propane is preferred for outdoor and winter work - butane stops vaporising properly as the temperature approaches freezing, so a butane setup can simply stop delivering gas on a cold morning.

These have an 8mm (5/16 inch) hose nozzle outlet, which takes a matching LPG-rated hose secured with an appropriate hose clip. Use hose made for LPG - we stock rubber and PVC LPG hose to the relevant standards - and never substitute general-purpose rubber hose. Check the hose for a date code and replace it at the interval marked on it.