Be sure to add me to your favorites list Yamaha Replacement Key For Yamaha DX-100, CS-01, CS01 II, Genuine Yamaha Replacement Mini Key Part. This is for one (1) half-sized mini key, a genuine replacement part from Yamaha, made in Japan. These smaller type keys are for the DX100 mini FM synthesizer keyboard and the CS01 mini analog synthesizer keyboard that uses this type of smaller mid-sized keys. They should also work for the CS01 II which is very similar to the CS-01, and most likely for the CBX-K1 mini keyboard controller and the CBX-K1XG controller / tone generator, but I'm not 100% sure about that one, so please look at the photos and compare. I have a few of each note available, and you can get one or more if you needed them. Just add the ones that you needed into your shopping cart before you check out. Again, these are NOT full sized keys, but the smaller sized keys that are half the size of full sized keys that are used in the models listed. The width of one of these keys at it's widest point is 3/4" of an inch wide. These are in very good condition, and I have several of them available. Price is for one key, and you can get one or more of any of the notes that are available. If the note that you need is unavailable, just message me and I'll double check to see if I have some more, which is entirely possible as I have a lot of keyboard parts around here. This is a replacement key part and price is for one (1) key. This is not an entire instrument. If you have any questions, I'm always happy to answer them. Thank you so much for looking! Please check out my Store!