The Noco HM426 battery box is a battery storage solution for dual 6V batteries. Ideal for installation in boats, RVs, campers, trailers, etc. Internal dimensions: 371 267 292 External dimensions: 455 363 356 The box has full flow ventilation for battery gases. Designed for dual 6V batteries. A four-corner mounting system for easy installation. Large cable holes for battery cable (up to 4/0 AWG). Large internal container to collect battery acid. Rugged, rotationally molded design for extreme conditions. Meets Coast Guard (USCG) Code of Federal Regulations 183.420. Meets American Boat and Yacht Council (ABYC) E-10.7.