"Center-fed 1/2 wave coaxial sleeve. 3dB gain. Heavy-duty construction for general purpose communications. It's at home on T-tops, Hard-tops and other positions aloft, where its small size can deliver maximum range. Brass and copper elements, stainless steel ferrule with standard 1"-14 thread. Includes 20' RG-8/X cable and PL-259 connector. Suggested mount: 4187."