I bought my fixed gear bike about a week ago. I've been out on it no more than 3 times. Last night as I was about to start riding I decided to check the rear lockring. It was loose!!! I tightened it with a screw driver and a hammer but I'm afraid it might strip the lockring eventually.

I went on performance and all they had was this. I'm not sure how to use that. I think I need this. Also, I have no idea what a good one (brand) would be. Lastly, I could use some guidence as to where to get one.

Thanks in advance.