The B65805C0100A033 is a ferrite core and accessory manufactured by TDK. It is a type RM 5 M33 100 + 3% - 3% ferrite core with accessories consisting of split bobbin and two straps (pairs). The core has a tolerance of 3%, which means it could be lower or higher than the nominal value. The core has two windings, one for each side of the core. It is made of ferrite, a magnetic material, which can be used to reduce interference in electrical circuits. It can be used in various applications, such as filtering, inductance, and tuning.