MRCOOL DIY25-1438-O DIY 1/4 x 3/8 Pre-Charged Mini Split 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 channel for refrigerant to flow between system components, enabling efficient heat transfer for cooling and heating operation. Designed for use with MRCOOL DIY ductless mini-split HVAC ... https://www.partshnc.com/mrcool-diy-line-set-diy25-1438-o