Tsubaki 40B17F-1 Finished Bore Sprocket， Single Strand， Hardened Teeth， Inch， #20 ANSI No.， 1/2" Pitch， 17 Teeth， 1" Bore</br></br></br></br></br></br></br></br></br></br></br></br></br></br></br></br></br></br></br></br></br></br><img src='http://ecx.images-amazon.com/images/I/41LoGLlMdBL.jpg' noproxy></br><img src='http://ecx.images-amazon.com/images/I/31Tz6SslwmL.jpg' noproxy></br><img src='http://ecx.images-amazon.com/images/I/515fgGG9hLL.jpg' noproxy></br><img src='http://ecx.images-amazon.com/images/I/4159e1YFMnL.jpg' noproxy></br>