Ferrite accessories are a variety of devices that contain ferrite materials. They are used in electromagnetic applications, usually as filters for ripple or noise suppression. Ferrite cores are shaped as a former for copper wires to be wound around and are used in chokes, antennas and EMI suppression filters.

Ferrite accessories are available in different materials and shapes referred to as series, which group them into devices optimized for the application. Such applications include larger ferrites used in high power supply designs. Ferrite cores for EMI suppression usually comprise of iron oxides, nickel and zinc and are physically configured as beads or split beads to go over cables and wires, or doughnut shapes.

There is a massive variety of ferrite products based upon a variety of materials and shapes. This includes materials that support high magnetic flux, have broad temperature ranges and provide for low losses of desired signals, but high losses for the unwanted signals that need to be suppressed. There are standard core shapes based upon international standards to ensure that ferrite accessories are compatible.

There are various shapes optimized for particular purposes. This includes planar shapes used for low profile products. Such shapes are usually a compromise to allow the devices to be better suited to the application, for example, a mobile phone. There are also special materials for high-frequency suppression and use in antennas and inductors to improve performance. Some materials compromise performance for high stress resistance, and some ferrite accessory series are available in kit sets to facilitate product designers in trying different devices in their circuits.