3-15/16" x 8-1/4" ( 3.9375" x 8.25" ), W-2 Poly Window Envelope, 1" x 3-3/8" Window, 1/2" From Left, 1-1/2" 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, 6 lbs. per Box