Handles up to 30 amps of solar Prevents battery back-drain through panels at night Reduces overall system maintenance Protects battery against temperature overage For use with solar arrays typically 15-22 volts, 25 volts max For use with 12V solar panels and batteries only. Overall dimensions: 8.8" L x 10.2" W x 2.2" H Shipping Weight: 0.85 lb.