0 Gauge 1/0 AWG Metal Firewall Grommet Bushing Audio Amplifier Wire/Cable Install Ultra Durable Nickel Plated Brass Bushings won't Rust/Oxidize or break down over time - Adds a Clean Look to your Install! Fits most 0 Gauge Amplifier/Battery Cable on the market! - Cable with an Outside Diameter of 1/2" - 11/16" (13-18mm) Can be mounted to Metal, Wood, Fiberglass, or even Plastic. (Such as Firewalls, Floor Pans, or even Speaker Enclosures.) Extra Long 3/4" Mounting Threads can be mounted in surfaces up to 11/16" (17.5mm Thick) Required Hole/Saw Size: 1 1/8" (29mm) - (Suggested tool: Hole Saw, Step Drill, or Knockout Punch.)