Quality Park Clasp Envelopes, Brown Kraft, 10 x 15 inches, Box of 100 (37898) Rugged with a secure seal 28 lb. 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.