iPhone 5 Bumper Case

Here is my version of an iPhone 5 bumper case. This is my first design of this scale, so I'm sure there are some imperfections, but I've been using test versions of this case for weeks now and it is very solid. There are a few cosmetic issues with a couple of the screw heads, but I designed it to fit in my cup holder, so I can't make it any wider to fix this.

Also, this case was designed to accommodate 0.4mm tempered glass screen protectors on the front and back of the phone. Not sure what t