The product is hi-duty nut/sleeve fitting, Brass, 1/4 inch compression tube. It features all Brass construction, no Flaring, soldering or other tube preparation, one piece nut and sleeve reduces installation time, use with copper, seamless steel and thermoplastic tubing, steel tubing must be cold drawn and annealed seamless low-carbon per SAE J524 with a maximum hardness of Rockwell B65.