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