5" x 11-1/2" (5" x 11.5" ), Regular Envelope, No Window, Western Sulphite, White Sulphite Paper, SFI Certified, Vellum Finish, Two Side Seams Under, Flap Down, Remoistening Seal, 500 Qty / Box, 2500 Qty / Ctn, 10.5 lbs. per Box