The Vevor dual battery isolator is a 12V 300A voltage-sensitive relay designed for dual-battery systems in vehicles and off-grid applications. It supports lithium and lead-acid batteries, automatically adjusts charging behavior, and offers both manual and automatic modes for flexible operation. An LCD screen provides real-time dual voltage monitoring, while the adjustable 3-60 second delay helps reduce frequent switching. Its durable housing and built-in overvoltage and undervoltage protection make it a dependable choice for cars, trucks, RVs, UTVs, ATVs, and boats.