Western Sulphite® Open End Catalog with Window Open End Catalogs have their flap on the short dimension. These envelopes are manufactured with white wove SFI Certified paper, center seam construction, a poly window and a traditional remoistening seal.White Sulphite (SFI CERTIFIED) 92% Brightness Vellum FinishCenter Seam Poly Window Remoistening Seal Flap Down