Whitworth Nut, for use on BSA models: C10, C11, C11G, C12, B31, B32, B33 & M20, M21 & M33O.E.M: 29-0905 / 29-905Thread: Whitworth 20 TPISize: 1/2"Supplied: SinglesWhitworth 1/2" x 20 TPI Nut, S204SKU: 29-0905 / 29-905£2.99PriceQuantity*Add to Cart