Single- & Three-Phase EMI-RFI Filters KEMET Single- and Three-Phase EMI-RFI Filters are available in a variety of shapes such as chassis mount, metal box, metal cylinder, plastic box, and plastic cylinder. These filters have the capability to cover single- or three-phase requirements depending on the application. The filters are optimized for both common and normal mode noise, and the filters come in different voltage and current ratings. Typical applications for these KEMET filters include general electronic and industrial equipment.