Originally Posted by dutret
A decent single tooth wrench is more then adequate so unless you are changing the cog frequently don't bother with anything better.
i've had nothing but frustration with single-tooth wrenches, as the contact between the concave part of the wrench and the lockring lifts the tooth out of the notch on the lockring and makes it slip. maybe i just wasn't using the best single tooth wrenches. either way, the three-pronged dealie addressed that problem.