On left: 15" Unibody fan. On right: 17" Unibody fan. Below: A North Carolina 'first-flight' quarter.

The Sunon manufactured fan says 'MagLev' on it. That's interesting! Part #: MG45070V1

Sunon's site says, "By using magnetic levitation force (MagLev), these fans feature zero friction with no contact between shaft and bearing. With excellent rotational stability, the MagLev fan eliminates vibration and typical wobble and shaking typically experienced in fan motors."

"MagLev also provides excellent high temperature endurance that results in long life."

Apple's used similar fans in MacBooks in the past.