Typical Applications: The toroidal core caps can be used as an alternate to the standard insulating coating when winding cores with very heavy gauge wire or when a greater dielectric strength is required. Core caps will fit either coated or uncoated cores. To specify a core that is uncoated add the suffix "/18" to standard part numbers. (Example: T400-26 is a standard part which includes coating, T400-26/18 specifies a standard part without coating.)