The battery powercord for the 2720 has a jack connector for speakers builtin and I have a waterproof mini-DIN connector in the wire going there from my helmet. If I don't have my GPS on, I have a piece of wire about 6" long hanging from the side of my helmet. That's long enogh to be able to see what you're doing (just) when plugging in the cable with your helmet on, and short enough not to even notice it without.
The wire plugging in my helmet is a curled wire so it is doesn't dangle all over the place, while still providing length when needed.
All in all, it works great, gives very good sound and it's a very convenient solution for me.
My kit. (25 euro)
Kit for the 2820, with stereo sound for the MP3 player, and mic to operate with a BT phone. (45 euro)
Hey, it works for me.
