Titan Chainring Nut Wrench
The Titan Chainring Nut Wrench is a simple, straightforward tool for use when working on your chainring bolts. It enables the mechanic to gain leverage and stop the female part of your chainring bolt from rotating while tightening or removing the male part of the bolt. The wrench can also be used for the same purpose on replacement derailleur hangers.
For $3 you don't need to worry about scratching your lovely shinny crank. but you need to be patient when you put it on so it won't slip.
Between this and the park wrench, this one is easier to handle. It is still difficult to really snug down as the aluminum nuts want to slip off the wrench. Still works better than a flat head screw driver though.