The TZ-230D-4h is a high power 4:1 50 ohm Balun designed to operate from 2 MHz to 30 MHz, covering the 80m through to 10m bands in a single balun. The balun uses a dual toroidal core with bi-filier winding for high efficiency and power rating. High temperature enameled copper wire is used to ensure the balun does not fail under extreme temperature, power and high VSWR conditions.