Sierra BS11000 2-Position Battery Switch - ONOFF w Alternator Field Disconnect The Sierra BS11010 Battery Switch is a 2-position switch with ON-OFF function and Alternator Field Disconnect AFD. This battery switch features a unique ergonomic and aesthetic knob design and a robust glass fiber reinforced nylon enclosure. Surface or panel mount options provide flexibility during installation and removable windows on all four sides allow for unobstructed wiring. Features Smallest battery switch with