Easy to fit - no alternator/trigger wire connection required. Red LED indicator. Max output 140 amps. Allows charging of 24 volt auxiliary/leisure battery bank without discharging the 24 volt starter battery. The voltage sensitive relay will make sure the starter battery is fully charged first before switching the charge to the leisure battery. Simple to fit. Cuts in at 27.4 volts and breaks at 25.6 volts.