Die-cut white fiberboard mailer ships and stores flat for easy storage until you need it, then folds quickly into a shipping box. Protects ring binders, catalogs and business forms. Easy to set up—no tape needed. Pre-printed address lines. For 3″ Binder. Box/Tube: Box; Box/Tube Design: Roll End Tuck Top; Length: 12″; Width: 12.25″.