The MRCOOL DIY Ductless Mini Split is truly a Do It Yourself product that can heat and cool your home quickly and efficiently. This is a DIY or Do It Yourself system because it comes with a pre-charged line set, which means you don't need special equipment to connect the refrigerant lines. The refrigerant lines are connected to the condenser using plunger valves, which contain protective rubber seals. That means no refrigerant is released until the lines are sealed and connected to the condenser. This keeps refrigerant from escaping into the atmosphere during the installation. There are no special tools needed to set up the system and refrigerant lines do not have to be vacuumed. Since the unit is pre-charged, you will not be handling any refrigerant, so no certification is required to buy or install this system. This MRCOOL Ductless Mini Split is specially designed as a do it yourself project for homeowners and business owners. The valves are designed to be leak-free and are backed by a seven-year compressor warranty and a five-year parts warranty.