The heavy-duty nylon zip ties are equipped with a locking mechanism, and are sure to give a sturdy, secure hold wherever you need it. A fast and easy way to secure ducting, filters, and more, these Zip Ties… The heavy-duty nylon zip ties are equipped with a locking mechanism, and are sure to give a sturdy, secure hold wherever you need it. A fast and easy way to secure ducting, filters, and more, these Zip Ties can fit up to 10” ducting and the 48” can fit up to 14” ducting. Sold in packs of 50. UL listed.