Kmc z1 narrow chainkmcs z1 narrow chain is designed specifically for single speed bikes or for bikes that have internal hub gears with 332 sprockets it has a bushless construction and higher inner plates to prevent chain drop features 12 x 18 112 128 links pin length 73mm for internal gear hubsingle speed high reliability compatibility single speed internal gear bmx track and fixed gear snap on joining link no dropbuykmc componentsfrom chain reaction cycles the worlds l