The Aeris Rail an aluminum bumper case for the iPhone 4 / 4s it retails for $109.99at their website. The Rail is a screw less design aluminum bumper that is retained in place with a plastic bumper.
More after the break.

The Rail is made in Australia and is constructed out of 6061-T aluminum using a 7-axis CNC machine. Then the Rail is colored with a high quality anodized finish for scratch protection. The power button is a 316 stainless steel that looks and preforms like the original button. The Rail is a hundred dollar case and the level of quality in this case is apparent when you see how precise the construction is.