1Powerful Function: The firewall boot is professionally designed to protect your wire harness from cuts and chaffing. Perfect for cables, hoses, conduits, and power lines to meet different demands, convenient for using. 2Cuttable and Reusable: The firewall boot is highly adjustable and reusable. You can easily trim to the next width if you need to add more wires. Accommodate anywhere from 3/8 inch to 1 inch bundles. 3Easy to Use: Need a 1/4 inch hole for installation, use a tool to cut the boot tapered end according to the wire bundle thickness. From there, all you need to do is install the firewall boot on the drilled hole and run the wire through it. 4Durable Materials: Universal firewall boot is constructed from superior rubber material which is weatherproof and anti aging, durable and long lasting to use. Sturdy and thick collars will tightly fit on the drilled hole. 5Universal Accessory: Not only in various wire harness thicknesses in automobiles, but also in ships, RVs, trucks, and even machines or in everyday life. Universal fit ensures that the wire bundles are tight no matter how thick or thin they are.