A new experimental inorganic fibre currently under development at the Du Pont Company is a continuous filament, polycrystalline a-alumina yarn designated Fibre FP. This fibre is suitable for reinforcing a variety of materials, especially non-ferrous metal castings because of a combination of properties such as high strength and modulus, stability at elevated temperatures, composite castability and potentially low cost. Fibre FP, essentially > 99 % a-Al 2 O 3 , is made by a novel continuous ceramic fibre process utilizing low cost textile fibre spinning technology and is produced as a yarn containing 210 filaments. The modulus of Fibre FP is 379 GPa (55 x 10 6 lbf in -2 ) with a tensile strength of 1380 MPa (200000 lbf in -2 ). The room temperature strength and modulus of the fibre are retained to about 1000 °C. Recently, higher strength FP fibres with a tensile strength of 2070 MPa (300000 lbf in -2 ) have been demonstrated on a laboratory scale.