this listing is for a set of 8 usa made APE replacement valve guides for the gs1000/kawasaki z900/1000/gpz1100/z650/z750/gs750/850/gs1100g shaft.. std size,they are a direct replacement for the stock guides. the superior material these are made of reduce guide and valve wear significantly over std. bronze ally guides are available for most models,new and classic,see our other listings