This is 12-48V DC Circuit Breaker has been designed to end the struggle of blowing fuses and hassle of having to buy and install more. A yellow arm will deploy when the circuit is tripped, then just simply reset the circuit. Item30A-300A Car Circuit Breaker with Manual Reset Car Boat Manual Power Protect for Power System Fuse 12V-48VDC WaterproofInputDC 12V-48VModel30A-300A Automotive & Marine Circuit BreakerOperating Temperature-32℃(-25℉) – 82℃(180℉)Material Black Plastic+MetalResettableManual reset button, manual control and easy to operate with manual reset arm, also can be used as a Kill Switch.Broad CompalitityMainly used for car audio and Amps protection and in trucks, boat, RVs , marine, buses etc; also used in battery charges and DC sound system. Works great for Solar systems, battery bank to solar charger. Power inverters.How to Find the Amps you Need!AMP= Watts / Volts x 1.25Example: AMPS = 1000 Watts / 12 Volts x 1.25 = 104.1 AMPS (Round up to 110 or 120 Amp) Most of the time you want 25% more than what is the actual requirement. If the AMPs aren’t available as the exact Amperage, then round up to the next available.