High-Current Battery Selector Switch for Marine & 4WD Dual-Battery Systems The Blue Sea m-Series Mini 3 Position Battery Selector Switch is designed for dependable, high-current battery management where clear isolation and simple selection matter. In boats, caravans, camper trailers and 4WD touring vehicles, battery systems are often asked to support critical loads such as fridges, lighting, comms, bilge pumps, winches...