I ride a motorcycle, and as fellow motorcyclist will know, wind noise reaches hearing damaging levels. Many wear foam earplugs but this blocks out too much, I noticed that earbuds, block the wind but let most other things through almost unhindered, like car horns. Wearing earbuds is illegal, wearing earplugs is not, having a helmet audio system is not. So after installing a helmet intercom/audio system, I wanted the protection of earbuds without the cord.
I came up with these, they accept skull candy, and probably many other tips from earbuds.

They work quite well as Is although I was thinking about a tube down the middle and some sort of stuffing in the larger bulb section like cotton or something. To let higher frequency through but not the roar of the wind.

EDIT, I have been using these a while now and they work better than expected as is, the round part could probably be shorter to make taking helmet on and off easier, but they block almost all wind but let the helmet system through just fine. When going slow in town it makes the helmet system quieter, but I can hear gps directions and song directions at highway speeds with these in, I couldn't understand vocals before without them.