Staples Gummed White Booklet Envelopes - 5-7/8" x 9-5/8" - 100 PackStock up on these handy Staples Booklet Envelopes for all your mailing needs. The classic open side envelopes measure 5 7 8" x 9 5 8" and have a gummed flap that closes securely and stays closed. Made of heavy 24 lb. white Kraft paper, these classic envelopes are ideal for cards, invitations or correspondence and come in a convenient box of 100 so you'll always have them on hand.