I did not believe it until

Initially, there were teething problems, since not accompanied by operating instructions. When I ansetzte the opener on a can passierter tomatoes, I was disappointed. Although I was able to turn the wing nut very easily, but it could not actually go. I also saw no effect at all. But when I found that the lid of the can could easily stand out and also close it again, I was shocked really. So that's just really a technique which can be met only with devotion. I think I'll never understand how the thing works. That it works reliably, which I have now can quite often convincing.