First of all, it has a full body PET protector, both on your screen and on the backside of the phone. This makes sure you won't get any scratches on your iPhone, not even when you have your iPhone with your keys in your pocket or something like it. As the back is also covered, your camera is protected as well from scratches.
It has a silicone ring. This is a big plus for this iPhone 4 case, as the silicone ring can absorb a lot of energy when you drop your iPhone on the ground. But silicone is not very protective against scratches and you cannot use it at all in front of the screen, so the solution found here is pretty nice.
And extra protective silicone materials at all your ports. I said already it is a hard core cover right? Your most important ports are protected as well, you have to remove the piece of silicone before charging your iPhone. I am not a big fan of this, but I can see how it would work. This protects your phone against dust and all other type of material what you will find in your iPhone after using it for a while.