The Rearth Ringke case for the iPhone 4 is a simplistic slim case that is made out of silicone but is also coating with a high polymer coating to reduce the amount of lint and dust from attracting to the case. If you're familiar with cases by SGP, the Ringke feels exactly the same as the Silke R case. The coating works very well and does not attract any lint to itself but because of this grainy coating you lose a lot of grip on the case and that isn't a such a good thing. I'm not a big fan of slippery cases that protect my iPhone 4, and the Ringke is one of them. Another downside to the Ringke case is that it has flimsy sides which tend to flex outwards and not hold their place. Read more for the full review after the cut!
The Ringke has a precise cutout in the shape of the Apple logo so you can shine it off to your friends, and I really like that but if you don't have some kind of back film protection, I would't recommend using this case just because your iPhone 4 could get scratched instead of being protected. The camera and LED flash cutout is very generous and does not affect the image quality. The volume button stays responsive however the volume buttons will require some force to push, so start working out. The cutout for the the silent switch is also very generous and easy to get to.
As you can see, you've got a pretty thin overlay on top of the screen. Overall the Ringke case for the iPhone 4 isn't so much of a good protective case for everyday use, even for it's price of $16.99 and vast color selection. There are better choices available out there.
The Ringz for the iPhone 4 are port covers for the headphones port and dock connector port. The Ringz actually works very well and might even save your iPhone 4 from water damage. They fit the iPhone 4's ports tightly and perfectly. You don't even need to use a case with the Ringz. It's a great way to protect your ports frm dust and small particles. The Ringz for the audio port come in a set of three for $1.99 and the dock connector covers come in a pair for $2.99. Both Ringz are available in many different colors.