The  20mm Clip-on Adapter is used to Convert 20 mm clip on Gas cylinders, such as used on Calor gas Butane gas cylinders, to 21.8LH screw thread. Output pressure through the adapter will be cylinder pressure. Normally connected to a bulkhead mounted 30mbar regulator via high pressure pigtails.also can be used to refill gas bottles with extra adapter.

Please note this adapter  is not a gas pressure regulator..