Meet the Syphon Soundwrap: a flexible speaker set that connects to your smartphone via Bluetooth and fits into helmets, hats, beanies, and everything else you put on your head. This soft speaker does not make you uncomfortable during long rides. It comes with 2 velcro strips and a sweat-proof sleeve.
The Syphon Soundwrap has 2 electrostatic flexible loudspeakers. It has 12 hours of battery life. You can pre-order one for under $200 at this time.