4-3/8" x 5-3/4" ( 4.375" x 5.75" ), Machine Insertable Announcement Envelope, No Window, Western Sulphite, White Sulphite Paper, SFI Certified, Vellum Finish, Side Seam, Flap Down, Remoistening Seal, 1-3/4" ( 1.75" ) Rounded Flap, 500 Qty / Box, 2500 Qty / Ctn, 5.5 lbs. per Box