Choose your typical adidas size, which ALWAYS run larger than other brands. The sound is good as well with balance in each area bass,treble and the mids. At the price point, or even above it, I can’t think of a better option. It’s just really the best design in my opinion. This thing is beautiful and sturdy, very well made. I wore this once and when I took it off my entire torso was red! It’s sturdy heavy duty and it can charge your phone at the same time They adapt well and work perfect for my needs! The app has slightly more functionality than the remote, but it’s trivial depending on your needs (see below). It would have been nicer still if they had included an adapter for thru-axles - if you dont have a QR rear wheel, you will need an adapter.