Voltage Max Operating: 58V DC, Amps Max Operating: 300A per block, Terminal Fuses Avail.: 30A-300A, Terminal Stud Size: 5/16'-18 (8mm), Mounting Hole Size: #10 (5mm)3/8' Compact, high-amp fuse-appropriate for DC Main, inverter, windlass, and bow thruster circuit protection Weatherproof - suitable for small open-cockpit boats and other harsh environments Insulating cap prevents accidental shorts Ignition protected when used with MRBF fuses Fuses sold separately