Their description:
Product Description
ToughSkin rugged rubberized case sports a distinct, textured pattern that protects your iPhone from accidental bumps and drops without adding bulk or limiting access to buttons and controls. The bottom of the case flips back for easy docking and the removable belt clip offers the freedom to carry your iPhone however you please…. More >>
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Speck Products Tough Skin Case for iPhone 3G, 3G S

Fits great and is comfortable to hold. All the buttons line up well for easy use.
Does what I need it to: protects my phone. Can’t ask for anything more.
I like the Speck tough skin with the exception of not being able to dock with the cover on. I knew about this and decided it wouldn’t bother me because I would use the USB cord to charge from my computer. I purchased a cradle dock and have to remove the cover every time I use the dock. When you remove the cover there is a protective hard plastic that protects the screen saver–you might damage the screen saver and have to replace it. But as far as protecting your iPhone 3g even when it bounces on the tile floor–it works perfectly. I also like the nubby rubberized skin because it is easier to hold onto.
It was advertised to fit Ipod Touch as well as IPhone 3G, but it is much too large for IPod Touch. So do not get it to use with the Ipod Touch!
Two days after I used the product, the holster dropped and lost my iPhone. It’s not sturdy. The swivel clip opens without noticing it. If it does, your phone would have probably been lost/dropped already.