A brass pigtail with a CGA 540 nut and tailpiece assembly at each end that connects to either a CGA 540 manifold tee or CGA 540 storage valve. Provided Oxy-Clean for oxygen service to 3000 psi. Additional Info: To join a series of commercial gas cylinders of the same CGA type, MANIFOLD TEES and PIGTAILS are needed. These are usually made of brass and copper, although stainless steel is sometimes needed at high pressures or in marine environments. TEES attach directly to the CGA tank valve, thereby providing two extra CGA outlets to interconnect two additional cylinders. Interconnections are made with a PIGTAIL, a metal, looped tube (or hose) with CGA nuts on each end. Loop construction permits spacing adjustments between cylinders and also absorbs sonic vibrations during compressing operations. Pigtails can interconnect tees or go directly to a compatible CGA tank valve.