ATO/ATC Fuse Block with Negative Block are used to provide over-current protection to help protect wiring in electrical circuits. For use with Sea-Dog ATO or ATC Style Fuses (445101-445130, 445190, 445156, and 445157) sold separately. Maximum: 30A per circuit @ 12 VDC. Constructed of injection molded ABS with tin plated copper contact and ground tabs. Installs with four #10 RH fasteners (not included).