Buying Garmin Zumo 220 GPS but need blue tooth ear piece

[flw]

I have never used any blue tooth devices so I know very little about them.

For the Bike GPS I'm going to buy (Garmin Zumo 220) I also need a blue tooth listening device.

I have no need to use it for a cell phone ever !!!

Since I only need to receive the signal for listening, can I get a tiny ear piece so it will fit under my helmet? I wear a full face helmet and it seems way too tight for a traditional blue tooth ear piece.

Any suggestions?