. Both models are excellent quality student model horns and some players even contend that the 21 is superior to the 23 because they were not as mass produced. I would say that they are at least equal in quality. Like all Yamaha instruments, this horn is very well made and plays well in tune. That is why Yamaha saxophones have consistently been the top recommendation by experienced teachers. This horn is in excellent playing condition. I have gone over it from top to bottom making repairs and adjustments as needed. I replaced a handful of pads and also put on a new compression resistant neck cork. As part of the process I also fully dis-assembled the instrument and cleaned it inside and out. It now plays easily from high F right on down through low Bb as you can hear in the attached video of this actual horn.This sax is also in excellent physical condition. There are no dents or dings of any significance, just a few tiny pings /nicks. The body is straight and the neck has not been pulled down or otherwise damaged. In terms of cosmetics, it does have lacquer wear and scratching consistent with a horn its age as can be seen in the pictures.This sax comes in its original hard wood shell case. The case is in very good condition. It is clean and odor free inside. The outside is in very good shape as well, although there is a bit of residue from an old sticker that was removed. It could probably be removed with a little elbow grease, or just place a decal of your choosing over the top to cover it up.There is also a plastic no name student level mouthpiece and unmarked ligature included. The mouthpiece is in good shape and works well with this horn. There are no additional accessories besides what I have already mentioned.