20 mm left-hand threaded adaptor for use with cylinders found in Italy and Greece.
Solid Brass construction
Female 20 mm left hand connection too 21.8 left-hand male thread.
 
Our pig tale high pressure hoses (4017 high pressure BS3212-2 hose or 4417 high pressure stainless steel hose) have M20 nuts each end, so to use this adaptor you need to connect to our 4012 adaptor and then connect to the regulator.