MRCOOL DIY16-3858-O DIY 3/8 x 5/8 Pre-Charged Mini Split Line Set 16 ft is a refrigerant connection kit designed to link compatible indoor and outdoor mini-split HVAC units. It works by providing a sealed, pre-charged pathway for refrigerant to circulate efficiently through quick-connect fittings, eliminating the need for vacuuming or specialized charging during installation. https://www.partshnc.com/mrcool-diy-line-set-diy16-3858-o