MRCOOL 4th Gen DIY Linesets are a new innovation in the HVAC industry that allows homeowners to install their own mini-split systems without hiring a professional. These linesets are pre-charged with refrigerant and come with quick-connect fittings that make installation easy and fast. MRCOOL 4th Gen DIY Linesets are compatible with MRCOOL DIY mini-split units and can be extended up to 25 feet. They are also leak-proof, corrosion-resistant, and flexible enough to fit any space. MRCOOL 4th Gen DIY Linesets are the perfect solution for anyone who wants to save money and time on their cooling and heating needs.