I bought this for a job on my truck because I saved more on labor than this cost. It’s not magic and can be awkward, but it does get stuff hot. I never could have removed some of the nuts and bolts without getting them hot, and I didn’t want to use a torch.
Once you get the coil hot, one touch against something will crumble the white insulation off of the coil. Also, the waves are just solid copper wire, and it would be easy to make them for custom applications; these coils can be easily bent at an angle to reach a tight spot. It's a valuable tool I’ll probably use a lot since I also work on old rusty tractors a lot.