MRCOOL DIY16-1412-O DIY 9K, 12K & 18K BTU Pre-Charged Line Set is a refrigerant line set engineered to connect compatible MRCOOL DIY mini-split indoor and outdoor units. It works by providing a sealed, pre-charged pathway for refrigerant to circulate between system components, ensuring efficient heat transfer for both cooling and heating. Designed for use with MRCOOL DIY 9K, 12K, and ... https://www.partshnc.com/mrcool-diy-5th-gen-16ft-1-4-x-1-2-line-set-r-454b-diy16-1412-o