These are a premium grade thermal binding cover that will work in nearly all thermal binding machines including GBC (except 1-step), Ibico, Fellowes, Covermate, and others. They have a rich grain-embossed finish on the back and spine, with a clear front cover. These are 6mm  covers which will accomodate 25 to 65 pages of 20lb. stock paper.  They are packaged 120 pcs to a box.