The RFS2-21-10-A5 is a ferrite core component manufactured by Essentra. It is designed to be used with flat cables, has an inductance rating of 26O, and measures 33.5mm in length in the A direction, 6.5mm in the B direction, and 10mm in the C direction. The component is designed for use in applications such as EMC filters, line filters, and noise suppression.