The Formula 4 features the same shaped iPhone 4 edge-banding that the gorgeous Vapor uses and adds a protective back-plate that's covered in a sheet of carbon fibre. The top and bottom edges bulge out slightly, while the right-hand edge features a rubber Element Case branded grip strip.
Gallery: Element Case Formula 4 for iPhone 4 | 8 Photos
The case is split into two halves. A top half that slides on and is most of the case. The removable bottom half slides off to let you dock your iPhone 4. When in use, the bottom half locks into place solidly and overlaps the top half just slightly, ensuring a good fit.
The Formula 4 encases the iPhone completely while the camera, headphones port, volume buttons, mute switch, the dock connecter, power button and speakers remain accessible. The screen itself is left completely uncovered, however, with the case providing only a very slightly raised edge. If you want screen protection you'll have to invest in a screen protector or look elsewhere.
Overall, the Element Case Formula 4 provides good looking, decent protection for the sides and back of your iPhone 4. It's not the thinnest of cases, with extra bulges at the top and bottom of the case, but it has decent ergonomics and doesn't add too much to the depth of the device.
If you fancied the Vapor, but couldn't justify the price or were worried about the aluminium affecting signal strength, then you won't be disappointed with the Formula 4. It combines decent protection and solid design, which makes it a winner in my book.