Park CNW-1 Review
This is a small tool that is used to hold one side of a chainring nut steady while you tighten the other side with an Allen wrench. It is also useful for holding the chainring nut while you loosen it.
Pros: The tool is small but it actually helps quite a bit.
It's cheap, so no harm in buying one.
The Final Word
Sooner or later you will need to replace your chainrings, so I suggest you grab a Park CNW-1 to help you do that.