3-13/16" x 7-13/16" ( 3.8125" x 7.8125" ), W-2 Poly Window Envelope, 1-1/4" x 3-1/4" Window, 3/8" From Left, 1/2" 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, 5.5 lbs. per Box