They work as intended; no more loosening tuning rods on your snare or toms. I play a lot of rimshots on the snare and the tuning rods under my left hand tend to loosen quite easily even after just a couple of hours of playing. Similarly, some tuning rods on the toms begin to come undone, especially after heavier hits. These tension locks prevent that from happening, at least nowhere near as fast. One pack is already enough to cover most of the problematic tuning screws, since you most likely need one or two per drum, and not a tension lock for every screw on a drum. I bought one pack and was able to cover two snares and four toms quite well.
If you have other than triple-flanged hoops, you might have some problems putting these in place. Happened to me with the diecast hoop on my snare, but not a major issue.