Vehicle Charge system : LED arrow mode activates when charge voltage reaches minimum 13.5V (v green LED) or ideal range of 14V+ (vv green LED) 4 LEDs cover æfull to emptyÆ voltage range of all 12V batteries, including higher voltage AGM for power sport (4th vv LED = 12.7V ) Monitor charge of stored power sport vehicle 12V lead-acid battery or confirm if the vehicle charging system is working correctly 2 automatic Modes û Battery charge level monitor (single LED blink mode) & Charging system test (arrow mode) Battery charge level : LED matching charge level blinks every 3 seconds (long term draw less than 0.2mA) 5A fuse with 5/16" / M8 ringlets. CORD MONITR 5/16-3/8 RING