Quality Park Gummed Kraft Clasp Envelopes, 7.5 x 10.5, Box of 100  (37875) Rugged with a secure seal 28 lb. Kraft Kraft with deep gummed flap Reinforced clasp design Clasp envelope on paper stock features a gummed flap closure. Double prong metal clasps with reinforced eyelets. Heavily gummed flaps. Reusable.