Package of 50 10" x 21" Brodart Fold-On Archival Book Dust Jacket Covers ***These high quality book jacket covers are Center-Loading for Dust Jackets up to 10" tall. ***The covers are 1.5 mil in thickness. ***Super-Clear polyester mylar. ***Overall dimension of these Book Covers are: 10" Tall x 21" Wide. ***Closed edges are permanently bonded. Paper backing for added protection.