Using this brass reducing union is easy. First, make sure the surfaces of the pipes you're connecting are clean. Then, attach the flare nuts to the pipes and connect the reducing union between them. When tightening, do it gently but firmly to avoid any leaks. As for the type of refrigerant gas, this product suits them all. Just make sure it's compatible with your refrigeration system. When it comes to maintenance, regularly check the union and nuts for signs of wear or damage. If you notice any corrosion, clean it off with a soft brush and a mild cleaning agent. If parts are severely worn, it's best to replace them. With proper use and care, this product will serve you well for a long time.