Aluminum brand new Chevy GM 100 amp alternator 10DN case style with v-belt pulley black finish. This alternator can be wired as a 1 wire style unit connecting only the hot lead to your positive side of the battery or starter solenoid. The side plug is optional connections for factory 3 wire harness vehicles. #1 terminal is for the check light and #2 terminal is 12 volt ignition hot. These connections are not required for the proper function of this unit.