If you want to mount prints that are flat, you need this. It measures 20" x 20" and is about 1/8" thick. It weighs 29 lbs. When your print comes out of the dry mount press (hot), you lay this on top of it, and when it cools, and the adhesive is solid, the print is flat. I'm thinking you can't find these anymore, and this thing is like new, pristine. I took good care of it.