DUAL BATTERY ISOLATOR 12V KIT – Measuring only 2.6" x 2.6" x 2", it's the perfect dual batteries isolation kit for under the hood or Battery Relocation Kit. Say goodbye to power-robbing traditional battery isolator diodes, solenoids, or battery disconnect switch 12v with our Battery Isolator 12V that delivers optimal performance without sacrificing power. DUAL BATTERY KIT by Keyline Charger is a Voltage Sensitive Relay that charges two battery systems. It ensures that the primary battery is always charged and ready to start the vehicle by cutting in at 13.3 volts and cutting out at 12.8 volts. It's like having two power sources with only one alternator. RUGGED DURABILITY: The ideal choice for those who require a reliable marine battery isolator or a dual battery smart isolator for their car audio battery charger needs. The KeyLine Automatic 140 Amp Dual Battery Isolator is a durable product that can withstand extreme weather conditions and vibrations. Its IP65 certification guarantees its safety for off-road use, even in dusty and wet environments. WHAT YOU GET: (1) 140 Amp Voltage Sensitive Relay (VSR); (1) 20 ft red battery cable; (1) 2ft black ground battery cable; (2) positive brass marine type battery terminals; (1) negative brass marine type battery terminal; tinned copper lugs & heat shrink; cable ties; easy-to-follow instructions. Easy-to-follow directions for the most novice DIYer. Power wire in, power wire out. What could be easier? BUY WITH CONFIDENCE: Every 140 Amp Dual Battery Isolator is backed by an industry leading 12-month warranty. If you are not 100% satisfied with your purchase, simply take advantage of the No Questions Asked, 30-Day Money Back Guarantee!!