One of the non-return valves my heat pump failed and i lost all my refrigerant the valve was different so i had to add copper tubing this tool allowed me to flare off the copper and instead only had one solder joint per port two if i used fittings try not to flicker all at once (although it will happen). I widened 7/8" copper and Pr about halfway, and then rotated the tool so the gaps between the mandrel sections are now even between the lines ight were created by the tool in the copper. Then I swung it to the end and also returned to its original position and swung it again. This makes the inner surface smooth instead of having indentations where the mandrel sections separate. Every connection was a perfect fit and hasn't leaked in over a month. Very happy with this tool even if I will never use it again!