FERROXCUBE TX Series Ferrite Toroids TX series range of ferrite toriods coated with epoxy which is flame retardant in accordance with UL 94V-0. These toroidal ferrite cores have a maximum operating temperature of 200°C and a 2000 V DC isolation voltage, contacts are applied on the edge of the ring core, which is also the critical point for the winding operation. These ferrite ring cores are available in a variety of sizes, please refer to datasheets for details.