Quality Park High Bulk Clasp Envelopes, Gummed, Brown Kraft, 10 x 13, 100 per Box, (37892) SECURE: Clasp closure plus gummed closure for reliability, security and ease of mind that your contents will securely stay closed in the envelope DOUBLE SEAL DESIGN -double prong metal clasps with reinforced eyelets and heavily gummed flaps ensure the envelope stays closed and durability MULTI-PURPOSE: These 10 x 13 envelopes are perfect for filing, storing or organizing documents REUSABLE-Great value, each box comes with 100 10 x 13 clasp envelopes that can be reused multiple times for a bargain DURABLE: Made from sturdy 28 lb. brown kraft stock