Blue Sea M-Series Battery Switch On/Off with Knob

The Blue Sea M-Series Battery Switch On/Off with Knob is the marine-grade electrical control point every serious boater needs at the helm. Whether you're running twin engines, managing house batteries, or isolating systems during maintenance, this switch delivers reliable on/off control with the tactile confidence of a solid mechanical knob. After years navigating everything from coastal runs to weekend cruising, you learn quickly that electrical reliability separates smooth days on the water from costly headaches at the dock.

Built by Blue Sea Systems—a name trusted throughout the marine industry—this battery switch features tin-plated copper studs engineered specifically for maximum conductivity and superior corrosion resistance in salt and fresh water environments. The studs accept standard 3/8" (M10) ring terminals, and the 7/8" (22mm) stud length accommodates multiple cable terminations without cramping your installation. The knob design provides positive engagement that won't slip or require guesswork in rough seas, and the compact footprint makes it ideal for tight panel layouts where space is at a premium.

Anglers and cruisers rely on this switch for emergency battery isolation, engine starting circuits, and house bank management across vessels of all sizes. Installation is straightforward for anyone comfortable crimping terminals and drilling a panel hole; existing marine wiring practices apply directly. Weighing just 0.62 lbs, it adds negligible weight while delivering the dependable performance you'd expect from a purpose-built marine component backed by decades of industry reputation.