the chain attached to your bike and a hammer and screw driver. It doesn't have to be insanely tight, just really tight. If its not tight enough you'll know when you take it on your test drive. I just put the cog on and hand tighten it, then put the lock ring on but only a couple of threads. Then I mount the wheel, lean against a wall and kinda jump on the pedal, then I rotate pedals forward 180 degrees and do so for the other pedal. After that thread the lockring on all the way and tap it with the screw driver. No need for new tools. BTW make sure when your tapping it you're pushing the lockring around the hub and not the metal part of the screw driver into the handle lol.