Set of 12 plus the envelope. Cards are similar in stock to picture packs, but measure 4.25"x 7", and average NM condition. The envelope itself was not opened carefully and has two large tears. Checklist is on the front of the envelope, key are Hank Aaron and Willie Mays. There is no indication of publishing date on either the cards or envelope, but the combination of players and uniforms narrows the possible range down to 1969-1971