Tariff classification change reassigns precured synthetic tyre tread to rubber sheet category, replacing earlier guidance. A Note 9 amendment to Chapter 40 extends the sub heading for rubber 'plates, sheets and strips' to items cut or surface worked to render them fit for resoling, repairing or retreading tyres. As a result, precured synthetic tread material produced by further working such plates, sheets or strips for resoling or retreading should be classified under the rubber plates/sheets/strips sub heading, and earlier instructions (Cir. 61/89) are modified accordingly.