Your car’s electrical power demands can change on the fly — and an XS Power alternator harness will help you adapt to them. These adjustable voltage controllers allow drivers to set output voltage anywhere from 10 to 20 volts. You can purchase the harness and module together or just the module for your dash panel. Other XS Power accessories include step-down modules for use with 16V secondary batteries. We ship power controllers free in the lower 48 states with a 60-day guarantee.