What are the shoes called that have the little "propeller" near the heel?

I am doing a project and could use the shoes that have the little propeller fan-looking thing built into the heel. I'm not sure what they are called. I'm trying to research them and are getting no where. I am looking for the name of them or where I could possibly find them online. I remember seeing someone I knew with them In the year 2006 if that helps any.