Ideal for use in air venting applications, these Imperial 36-in Adjustable Tie Straps can be easily secured around flexible air duct with no tools required. Each nylon duct tie features a handy bent tip design for ease of insertion, and adjusts and locks quickly around the duct. Despite their compact appearance, these ties are constructed from durable nylon and boast a tensile strength of 175-lbs for lasting use. Available in a convenient pack of 50 duct ties, you'll have enough for all your duct fastening needs.