RM Cores Fair-Rite Power Inductor RM Core configuration allows better shielding than E type geometries while providing easier winding accessibility and better power dissipation than a POT Core configuration. Fair-Rite Products RM Cores all have a solid center post and standard height and can be supplied with the center post gapped to mechanical specifications as well as an AL value. Fair-Rite Power Inductor RM Core is available in a range of sizes from RM4 to RM14 and 3 materials with Initial Permeability ranging from 2300 to 3000.