I recently decided to install a heat pump on our new home rather than pay more than twice the cost to have it done. I was a HVAC professional in my youth (long ago). We used to use the tubing springs to bend the tubing and that is fine if there are no fittings, it is not flared already, and you are working at the last few feet of the line. I had need to make bends outside at the condenser, under the house in less than 24\" of space and then a tight bend at the air handler. The documentation is not written by an English speaker so is a little lacking but will get you by. They could have done better with explaining \"How\" to use it. There are places where you can bend from the inside of the curve but others where you must bend from the outside of the curve. That is what the two attachments are for that they do not explain. All in all I was able to make the correct angles outside to align perfectly so there was no binding. Under the house I was easily able to put a 90 degree bend in a 3/4\" line where I only had enough room to drag and not crawl. At the air handler, it made a very nice 90 degree bend that had to bend away from me in both the 3/4' and 3/8\" lines. I think this tool was worth the cost in time saved as well as the frustration you get when you finally kink the line you are so carefully trying to bend. At the price of copper now, you can not afford to buy another line set. If I only use it once (I doubt that) I would count it worth it on the installation cost.