Using this refrigeration brass flare union kit is easy. First, make sure the refrigerant system is turned off. Then, connect the 1/4 inch SAE flare union to the appropriate pipes, and use the heavy - duty flare nuts to secure the connections tightly. When using, always check for any gas leaks around the connections. As for maintenance, keep the kit clean and dry. If you notice any signs of corrosion or damage on the brass parts, replace them promptly. Store the kit in a cool, dry place when not in use to prevent any deterioration. Also, make sure to use it only with the appropriate refrigerant gases as stated, to avoid any potential safety issues.