Battery Doctor 20090 12-Volt Battery Isolator (100 Amps Peak)Water-resistant (IP62)Suitable for marine use Smart technology monitors the aux battery & keeps it chargedPriority charging for starting batteryOvercurrent & surge protected for vehicles with electronic systemsManual override for starting batteryCharge rate depends on alternatorDraws 300mA on standby modeManual override button allows both batteries to be wired in parallel for startingIncludes mounting bracket100A peak12-Volt Battery Isolator (100 Amps Peak)