3-5/8" x 8-5/8" ( 3.625" x 8.625" ), Double Poly Window Envelope, Top Window 7/8" x 3-1/2" Window, 5/8" From Left, 2-1/4" From Bottom; Bottom Window 1" x 4" Window, 5/8" From Left, 5/8" From Bottom, Western Sulphite, White Sulphite Paper, SFI Certified, Vellum Finish, Diagonal Seam, Flap Down, Remoistening Seal, Blue Wesco Tint, 500 Qty / Box, 2500 Qty / Ctn, 6 lbs. per Box