The MRCOOL GCNV-VUAB-3834 GeoCool No-Vac Vertical Upflow with Air Box is an HVAC installation accessory designed for compatible GeoCool geothermal heat pump systems. It works by providing a pre-configured vertical upflow connection with an integrated air box, enabling efficient airflow management and simplified refrigerant line installation without requiring system vacuuming during se... MRCOOL GCNV-VUAB-3834 GeoCool No-Vac Vertical Upflow With Air Box