The 00-21 has always been made as a 12 frets-to-the-body, slot-head guitar. In the early 1930s when other models began being made as 14 fret, solid headstock guitars, the 00-21 continued without any changes, keeping the 12-fret/slot-head design. It was "discontinued" as a regular production model in 1987 but has always been available from Martin direct by special order.
