Description: Unique ergonomic and aesthetic knob design (Patented) Knobs removable for isolation / safety Smallest battery switch with AFD (Alternator Field Disconnect) feature in market Robust Glass Fiber reinforced Nylon enclosure Removable windows for unobstructed wiring Compact size matching mainstream products in market Surface or panel mount options provides flexibility when installing Specification: Size: length: 69mm/2.7 inch, width: 69mm/2.7 inch, height: 73mm/2.87 Inch Mounting hole spacing: 54.8mm/2.15 inch Installation method: 1.Surface Mount ;2.Panel Mount Features: High rated current Protects your alternator Versatile cable entry Stud size: M8 5/16" Function: 1-2-Both-Off Continuous Current: 200A Surge Current (5min): 300A Cranking Current (10sec): 1000A Voltage Rating(Max): 48Vdc Installation: Alternator is the generator on the ship to charge the battery Wiring is Alternator - Battery Switch - Battery The battery switch cannot be turned off when the alternator generator is started. Otherwise, the generator's electricity will not have an outlet voltage, and the generator will burn off the generator's diode. So the correct way is to turn off the engine generator and then turn off the battery switch. The AFD function is that the two screw feet can be connected to the Field end of the Alternator. The AFD screw foot will open the circuit before the battery switch is disconnected, and shut down the Alternator. That is, before turning off the battery switch, she will automatically turn off the alternator (through these two screws) Avoid burning the Alternator. Package Includes: 1 Piece Battery switch 1 Piece Function identification sticker Note: With AFD(Alternator Field Disconnect) AFD cuts alitemator off before battery switch turned off,Thereby protecting the alternator