This chainring is available in 2 widths, 3/32- and 1/8-inch (thinner and thicker, respectively). You need to get the width that matches the chainring and chain on your bicycle (chains are designated as 3/32- and 1/8-inch, too). 3/32-inch is compatible with most bicycles with multiple gears and derailleurs. It's also used on many fixies, though not exclusively, so be sure to measure your existing chainring. Because there are no derailleurs and because the chain and chainring are under the greatest stress when riders race on a track, the 1/8-inch chainring and chain is used on most track bikes (and some fixies). Please ask if you're not sure which model is correct and we'll advise you.