These pieces are very rare, New York Meyer, 3m original metal alto.  This has got to be from the 1940’s or early 1950’s at the very latest.  There are VERY few of these around anywhere.  it is a large chamber handcrafted mouthpiece with an attached ligature like the old Master Link models and this one is in very nice condition.  This is a great addition to your vintage Meyer treasure trove and will certainly provide vintage sauce for your alto.