The Attenuation Station includes a selection of toroidal suppression cores in different sizes ideal for winding common mode chokes. This kit allows engineers to experiment with different materials and sizes to achieve the required amount of impedance. Including five materials to target EMI from as low as 100s of kHz to over 1GHz. Separating these from normal ferrite toroids, these are rated and built to impedance specifications as opposed to the normal low frequency inductance factor and maximum loss factor specifications.