All-Round Protection: Featuring overvoltage and undervoltage protection, the dual battery smart isolator is sturdy, durable, shockproof, and dustproof. It provides stable and reliable power for your RV, truck, boat, or off-grid system Dual Voltage Display: The high-brightness display shows the accurate voltage of the two batteries in real time (range 4.5V-20V). Our 12v split charge isolator can easily diagnose circuit problems and confidently master the system status Intelligent Delay Function: With an adjustable delay time of 3-60 seconds, this VSR isolator effectively avoids frequent switching, significantly extending the service life of the isolator and battery Manual & Automatic Modes: No more breakdowns! This voltage sensitive relay enables one-click switching to manual mode, letting your fully charged auxiliary battery reverse-charge a depleted main battery. No jumper cables needed—start the vehicle instantly High Battery Compatibility: Our dual battery isolator can adjust start-stop voltage, compatible with lithium, lead-acid and other battery types. No compatibility worries, it provides optimized charging experiences to maximize battery lifespan