How to protect the back of your iPhone with only a bumper?

I just got the iPhone 5 so I'm new to the whole iPhone family (lol) and all my friends talk about the bumpers that they buy so I bought one off of amazon and just got it and I didn't realize it was just for the side if the phone so what else do I need to protect the back of the phone (I already have a screen protector on the front)

Get a back protector. It's like a screen protector but for the back of the phone. Or just get a regular case!

Get a protector for the back. My package came with one for the back but i I never put it on because I thought it didn't look good. But I have this case now image

So the sides are like rubber and the back is this clear plastic but its pretty hard and there's no front like an otterbox.