These high quality book jacket covers are Center-Loading for Dust Jackets up to 12" tall. The covers are 1.5 mil in thickness. Super-Clear covers protect from harmful UV rays. Overall dimension of these Book Covers are: 12" Tall x 24" Wide. Closed edges are permanently bonded. Paper backing for added protection. These ARCHIVAL quality covers are completely acid-free and perfect for your most highly-valued books!