UniBind SteelCrystals are unique thermal binding covers with a clear acetate front and back cover. The steel spines are covered in your choice of 7 colors. SteelCrystal Covers have a thermally activated adhesive in the spine that securely holds your contents. THESE HAVE NOW BEEN DISCONTINUED BY UNIBIND AND ARE REPLACED BY THE UNICOVER FLEXCOVERS, WHICH ARE MATT ON ONE SIDE AND CRYSTAL ON THE OTHER. WE HAVE LISTED THEM SEPARATELY ON AMAZON.