0.4mm special shim for handlebar internal control rod. These are needed to eliminate all the play from the throttle and gearchange controls on the handlebars. Please note that normally a few of these shims are required, in both 0.4mm and 0.6mm sizes. The brass control roller in the pics is for an indication as to where these shims are fitted and is NOT included in the purchase price.
If you need 0.6mm shims, see Item : B184