The RAM® Fish Finder Mount for Humminbird Devices - B Size Medium (RAM-B-107U) is a light-duty solution for securing smaller marine electronics to your vessel. It includes a device-specific ball base, a medium-length double socket arm, and a 2.5" diameter round drill-down ball base with the universal AMPS hole pattern. The mount is fully adjustable, allowing users to quickly dial in their ideal viewing angle. Compatible devices include Humminbird 100, 300, 500, 600, and 700 series; Humminbird Matrix Series (excluding Matrix 97); Lowrance Elite-5, -5M, and -5X; and Raymarine Apelco fish finder units with a matching hole pattern.