I posted this image in my log, and got blown up via PM with lifters asking about 'where I bought the Zercher pad from'...
Well, we actually stole it from a couch or something but the availability of pieces of foam like this is high. I would imagine even places like JoAnn Fabrics or Michael's would have something.
The small inner square piece is glued only on one side, and the bar fits snuggly in the V.
If you have questions, SHOOT. - You're tendons can thank me later.