MRCOOL MC25-1438 9K & 12K BTU Flared Line Set Kit 25FT 1/4" x 3/8" is a refrigerant piping kit designed to connect compatible indoor and outdoor ductless HVAC units. It works by providing dedicated liquid and suction lines for efficient refrigerant circulation between the indoor air handler and outdoor condenser, supporting proper heat transfer. Designed for use with compatible MRCOOL... https://www.partshnc.com/mrcool-25ft-1-4-x-3-8-flared-line-set-kit-mc25-1438