The Hohner Pocket Pal is a simple diatonic harmonica. Hohner has marketed it as a harmonica that you can bring on the go, hence the name 'Pocket Pal.' However, there is really no difference between this and other diatonic harmonica, as any would be small enough to bring on the move. The Pocket Pal comes in the key of C, and I'm not sure if they have other Pocket Pals that have different keys, but the one that I have is in the key of C. It's pretty much your standard harmonica. Harmonica isn't one of my primary instruments, but I do have a bunch of them in addition to the Pocket Pal in a number of different keys. The other ones that I have are also made by Hohner, and it's really hard to tell too big of a difference between the Pocket Pal and the other harmonica that I've got. I don't think that I'd recommend the Pocket Pal for an experienced harmonica player - rather, I'd say it is best suited for someone who is looking to get their feet wet with the harmonica and who want something really cheap just to get started with. Of course the downfall with buying a single diatonic harmonica is that you can only play in a single key - in this case the key of C. I would imagine though that this would be okay for a beginner who just wants to try out the harmonica and see what it is all about. I'm not a harmonica connoisseur, but it doesn't take an expert to know that there are better harmonicas out there to be had. Having said this, if you want a single key harmonica just to get started with, the Hohner Pocket Pal is a more than adequate harmonica...