How to use: First, make sure your refrigeration system is turned off. Then, connect the 3/4 end of the reducing union to the corresponding pipe and tighten the 3/4 flare nut. Next, connect the 5/8 end to the other pipe and tighten the 5/8 flare nut. Ensure a secure connection to prevent gas leakage. Note: Always wear protective gloves and goggles when handling the product. Do not over - tighten the flare nuts as it may damage the parts. Maintenance advice: Periodically check the connections for any signs of wear or leakage. If you notice any issues, replace the parts immediately. Keep the product in a dry and clean place when not in use.