4" x 6-3/8" (4" x 6.375" ), Open End Catalog Envelope, No Window, Western Sulphite, White Kraft Paper, SFI Certified, Vellum Finish, Center Seam, Flap Down, Remoistening Seal, 500 Qty / Box, 5000 Qty / Ctn, 5 lbs. per Box