This product is a used engine casing with bearing suitable for BSA Triumph Norton Ariel motorcycles. Specifically designed for Triumph motorcycles, this part is ideal for replacing worn-out or damaged engine covers. The manufacturer part number is not specified, but the product is a genuine replacement part for these classic motorcycle brands. Please note that this listing does not include the specific make or model of the engine casing, making it a versatile option for various Triumph, Norton, and Ariel motorcycles.