43 Material Toroids Fair-Rite 43 Material Toroids feature a ring configuration that makes ultimate use of the core's intrinsic ferrite material properties. Fair-Rite 43 Material Toroids have low-medium permeability. They are ideal for use in a variety of inductive component applications, including power input filters, ground-fault interrupters, common-mode filters, pulse transformers, and broadband transformers.