ID America created this brushed aluminum case to fit the iPhone 4 and 4S. Designed to look like a head gasket, the case will be instantly recognizable to anyone who has spent time under a hood with a torque wrench.
The brushed aluminum should also appeal to gearheads. The case is lined with suede so as not to scratch the iPhone.
It grips well, with sides that come up just over the iPhone's bezel. Cutouts give access to all ports and buttons. But the gasket holes and overall low profile do not look like they offer much actual protection.
ID America sells the head gasket case for a $29.95, and it is available in six colors.
Just be prepared for friends making jokes about your iPhone's compression ratio.