This is a 48" 12 harness rug loom from AVL. Their rug looms are extremely sturdy and can hold an amazing tension. I have woven a few rugs plus other items such as table runners and a throw. It is very good for weaving anything from heavy rugs to lightweight fabrics. I am the second owner and although I've had it for many years, I have used it very little.

It is air operated with air for raising the harnesses up and then down in two separate motions.

First photo is a stock photo from AVL linked to their web page with information about the rug loom. All parts look the same except mine does not have the handle on the beater. Please keep in mind that their photo is of a current model and there may be other differences. 

Click on the photos for an enlarged view.