Western Sulphite® Open End Catalog with Kwik-Tak® Open End Catalogs have their flap on the short dimension. These envelopes are manufactured with white wove SFI Certified paper, center seam construction and a pressure-sensitive seal that requires no moisture. Release tape covers the adhesive until the envelope is ready to seal.White Sulphite (SFI CERTIFIED) 92% Brightness Vellum Finish Center Seam No Window Pressure Sensitive Seal Flap Down