Genuine Daikin 139758J Outdoor Cross-Fin Main Condenser Coil is the main cross-fin condenser coil in the outdoor unit that carries refrigerant through the fins so it can give up the system's heat to the outside air. When it is damaged, blocked, or leaking, the unit can lose output, run hot, or lose refrigerant. A genuine coil fits and performs the way your Daikin expects — where a non-genuine part can flow wrong or fit poorly.