This is a vintage Gregory "Master Model" alto mouthpiece. It is an all original 4A18M piece with the medium chamber and measures .065".
The piece is very nearly flawless physically, with just some minor marks on the bite plate and no major scratches of note. There is some minor oxidation but that's about it. The lettering is not worn, and the tip, rails, and table all look incredible. This is a fantastic piece for the player looking for the darker west coast jazz sound.