The Weltonhurst inlet Relief Valve fits the King Keg and Weltonhurst Basic Barrels. For use with the Hambleton Bard S20 and S30 Cylinders only.
For updating your old barrel cap, perhaps replace the old aluminium inlet relief valve or the Basic Barrel simple relief valve only caps.
All brass with rubber valves. Note you will need a similar but different valve for use with Sodasyphon sparklet bulbs. please enquire.