Roptex® (Brown Kraft) Open End Catalog Open End Catalogs have their flap on the short dimension. These envelopes are manufactured with a durable, SFI Certified Brown Kraft that has a vellum finish, center seam construction and a traditional remoistening seal.Brown Kraft (SFI CERTIFIED) Vellum Finish Center Seam No Window Remoistening Seal Flap Down