If you want to play recorder but have fewer than eight fingers the current options are all very expensive. This is a problem in elementary schools that use the recorder as a very cheap instrument that everyone can play. Some friends of mine figured out how to make an attachment for a standard soprano recorder that adds keys for the lower three holes:

They're running a kickstarter, and they're much cheaper than existing options ($20). I got a chance to play with a prototype, and thought I'd share my thoughts.

My first hope was that it would be a one-handed design, where I could play two at once for harmony and melody, but it's not. You need to cover five holes plus a set of three keys. It uses Baroque fingering, not German. Serious recorder players want Baroque fingering because it's better suited to chromatic playing, but Baroque fingering is more complicated for straight-ahead diatonic playing. Since that's what elementary schools are doing, I think they should all be using German fingering. While I can't really blame Triple Play for wanting to use the same set of fingerings as everyone else in the class, I can blame music teachers everywhere for pushing Baroque where it's less suited.

While we're complaining about instrument choices, really it should be a tin whistle. Those have only six holes, and have simple fingering comparable to German-fingered recorders. In a parallel world where schools used tin whistles instead, adding three keys to one would get you a one-handed version, which would both allow self-harmony and allow a wider range of people with limb differences to play. And actually, if you're using a tin whistle, with its cylindrical outside, you could use a telescoping external slide to control which holes were covered. Then it would be accessible for even more players; it would only require a single arm.

Back to the instrument that actually exists, in the music classroom as it actually exists. It worked pretty well: while I found I had to press the keys harder than I expected to get a good seal I got used to that pretty quickly. This may have been a prototype issue, due to the limited resolution of the 3D-printing.

I didn't play long enough to really get practiced with it, but I was pretty quickly able to play simple tunes using my left hand and right fist.

After a bit of playing, perhaps too intensely, I broke one of the prototypes. The 3D-printed attachment glues to the body along just a thin line, and I pushed it too hard. The final design, however, is made out of much sturdier plastic with a much larger contact area, so this is probably just another prototype issue.

Overall: I'm pretty glad this exists, in that its 10x lower price means in practice many more students who would benefit from one are likely to end up being able to use one.