The MRCOOL DIY50-3858C DIY 4th Gen 24K–36K BTU Connection Line Set is a 50-foot refrigerant line set designed for compatible MRCOOL DIY ductless mini-split heat pump systems. Featuring 3/8-inch liquid and 5/8-inch suction lines, it connects the indoor and outdoor units to enable efficient refrigerant circulation during heating and cooling. Designed for DIY installations, the line set simplifies system setup while supporting reliable performance. It is ideal for residential HVAC applications, offering installation flexibility, dependable refrigerant transfer, reduced installation complexity, and efficient operation for compatible 24K–36K BTU systems.