Blue Sea 7621 ML-Series Automatic Charging Relay (Magnetic Latch) 24V DC 
Manual Control: No Coil Voltage: 24V DC
Combines battery banks during charging and isolates under discharge
500 Ampere continuous rating suitable for use with large battery banks, starters, alternators, and inverter/chargers
Can be remotely combined with optional switch
Silver alloy contacts provide high reliability
3/8" copper studs, using Blue Sea Systems superior one piece stud technology, suitable for 300 Ampere continuous rating and large cable connections
WARNING: This product can expose you to chemicals including di(2-ethylhexyl)phthalate (dehp) which is known to the State of California to cause cancer, birth defects or other reproductive harm. For more information go to P65Warnings.ca.gov.