I had recently had trouble with my older tub fixture having leaks, so I went down to a local mom and pop hardware store and bought a similar item but it was plastic. After literally hours Of struggle with getting a good bite on the plasic one I gave up and went to my Home Depot and found a metal one. MUCH BETTER!
This one was made of metal and even though it was a very hard to reach area, it was much easier to get a bite with the tools on this metal one. It works very well. I would recomend using metal ones like this every time especially in a hard to access area.