Features: _x000D_Dimensions fits Heavy Duty Modular Fuse Box Series (BF43x) and Battery Switch, matching mainstream products in market. _x000D_Once your main starter battery is sufficiently charged, it will begin charging the second battery too. _x000D_A voltage sensitive relay (VSR) is the best way to ensure you can always get your dual-battery vehicle started. _x000D_Surface or panel mount options provides flexibility when installing. _x000D_No voltage drops comparing to battery isolator diodes (0.6V). _x000D_It has a solid glass fiber reinforced nylon shell. _x000D__x000D__x000D_Specifications: _x000D_Condition: Brand New _x000D_Material: Nylon _x000D_Color: Black _x000D_Size: 7 * 7 * 6cm / 2.8 * 2.8 * 2.4in _x000D_Nominal Voltage: DC 12V _x000D_Combine / Open Voltage: DC 13.3V / 12.8V _x000D_Continuous Current Rating: 125A _x000D_Intermittent Current Rating: 140A _x000D_Power Consumption: 10mA (Standby) / 330mA (Engage) / 0mA (Storage Mode) _x000D_Certification: CE IP67 _x000D_Package Weight: Approx. 234g _x000D__x000D__x000D_Functional Features: _x000D_After the engine stalls, the left House battery discharges to the upper left load device, and the VSR disconnects when the battery voltage drops below 12.8V. The Start Battery on the right will not discharge to the device. When the battery on your left is not charging, it is used up. At least there is a little battery on the right that allows you to start the engine. _x000D__x000D__x000D_Packing list: _x000D_1 * Voltage Sensitive Relay (VSR) _x000D_4 * Screws _x000D_1 * Manual 1Dimensions fits Heavy Duty Modular Fuse Box Series (BF43x) and Battery Switch, matching mainstream products in market.? 2Once your main starter battery is sufficiently charged, it will begin charging the second battery too. 3Surface or panel mount options provides flexibility when installing. 4No voltage drops comparing to battery isolator diodes (0.6V). 5It has a solid glass fiber reinforced nylon shell.