COMPATIBILITY: Compatible with Shimano type free wheel - easily to be removed or installed by freewheel tool. Inner diameter 34mm.<br/>Choices: Chain compatibility: 1/2"x3/32" . Teeth: 18.<br/>QUALITY: Made of high quality hardened steel. Tough and long lasting.Weight: 171g=0.37lbs<br/>BEARINGS: Quality ball bearings which rolls smoothly.<br/>