Features - Integrated pressure gauge for safety. - Dump valve for safe and controlled release of gas. - Used to safely refill cylinders from larger donor cylinders. - With a dump / purge valve to safely release the residual gas within the adapter once refilling is completed. - Includes a pressure gauge to ensure the pressure of the donor cylinder will not exceed the pressure specification of the recipient cylinder. - Designed to allow refilling of DIN 477 / W21.8 / BS 341 No. 8 CO2 cylinders, or you can add an adapter for refilling of SodaStream or Paintball / CGA 320 cylinders.