CB radio antenna 3-Way Mirror Mount with SO-239 Stud. Heavy duty stud and great for mounting all types of antennas with the standard 3/8" x 24 thread attachment. Works great with a 2' fiberglass antenna to a Wilson 2000 Trucker style antenna. Can be mounted on a tool box if you're willing to drill extra holes. Clamping bolts are approx 2" but you can decide to buy longer ones if you're looking to mount on a larger post like a brush guard. Easy to install, and guaranteed to last! Pro trucker offers the best CB accessories in the industry.