The Park lockring spanner (
http://www.parktool.com/products/det...=25&item=HCW-5) is very functional and a bit cheaper than the Hozan pliers, I think. I've used it on track lockrings and bottom brackets. Those pliers are nicer to use and give you a better grip, plus the serrated area can be used on knurled headset cups. Nothing wrong with the Park one though, if those features aren't useful for you.