Terminal Fuse Blocks mount on 3/8" (M10) battery post, battery switch and busbar terminals. Appropriate for DC Main, inverter, windlass, and bow thruster circuit protection, providing high current protection in tight spaces. Weatherproof and suitable for open-cockpit boats. Insulating nut and cap. M8 (5/16") terminal stud. Compact, Terminal Fuses are ignition protected and meet ABYC requirements for DC Main circuit protection on large battery banks. Clear window for visual indication of blown fuse and color-coded for each amperage. Terminal Fuses must be used with Terminal Fuse Blocks 5191 or 2151.