Quality Park Clasp Envelopes, 10x13, Box of 100 (37897) Clasp envelope on paper stock features a gummed flap closure. Double prong metal clasps with reinforced eyelets. Reusable. Heavily gummed flaps. Clasp envelope on paper stock features a gummed flap closure. Double prong metal clasps with reinforced eyelets. Reusable envelopes. Heavily gummed flaps.