5-1/2" x 5-1/2" ( 5.5" x 5.5" ), Square Envelope, No Window, Western Sulphite, White Sulphite Paper, SFI Certified, Vellum Finish, Side Seam, Flap Down, Remoistening Seal, 1-7/8" ( 1.875" ) Square Flap, 500 Qty / Box, 500 Qty / Ctn, 7.5 lbs. per Box