Used on aircraft. tee, hose barb, brass brass double-barbed vacuum hose or tubing; vacuum rating 29.9 inch hg at 72 degree f; pressure rating 100f at 73 degree f tee
Used on portable oxygen test set, nsn 4920-01-511-0092. connector assembly, mask port item is a qd connector, with a short piece of hose attached by 2 hose clamps.