Daystar's Firewall Boot is the best way to run wires, hoses, and other lines through your vehicle's firewall. Simply drill a 1.25 inch diameter hole in the firewall and install the boot. Run your wires, trim the boot as necessary to one of three different sizes (3/8 inch, 11/16 inch, or 1 inch), and secure the assembly with a zip tie. Safely and cleanly run wires through firewalls and bulkheads Protects wires from sharp edges; prevents wire chaffing and shorts Eliminates air/water leaks Fits a variety of wire thicknesses and bundles from 3/8 inch to 1 inch; 1-1/4 inch hole required for installation Works great for tubing and air lines