6" x 9", Neopost Machine Insertable Open Side Booklet Envelope, No Window, Western Sulphite, White Sulphite Paper, SFI Certified, Vellum Finish, Side Seam, Flap Down, Remoistening Seal, Neopost, 500 Qty / Box, 500 Qty / Ctn, 11 lbs. per Box