Can You Name This Item?

I can. I had one.

It is a "slide rule."

It performed difficult calculations of many different kind.

It became an icon indicating what today we would call "geekiness."

It could be worn in a carrying case on the belt.

It didn't fit into a pocket protector. (I didn't have one of those.)

Well, according to the website The Awesomer it is now being produced for the retro-geek. The ThinkGeek company had to start from scratch since no factory exists anymore to make them.

Amazing.