Not for tiny people but sweet otherwise
I bought the XS/S and I'm 5'1" and 105 lbs. This thing is supposed to be like a helmet for your spine. It didn't fit me, but that's not too surprising, since I'm rather youth-sized. I'm gonna return it and checkout some kids stuff =P
Otherwise though, this piece of equipment looks really sweet and is well-constructed. It will work for anyone with an average build, I'm guessing.