IWTX-4646BE-50 Wireless Charging Transmitter Coil Vishay-Dale IWTX-4646BE-50 Wireless Charging Transmitter Coil offers durable construction and high permeability shielding. This coil provides greater than 70% efficiency at a 19V input voltage when tested using WPC-compliant transmitter and receiver chipsets and an IWAS-4832FF-50 receiver coil. The Vishay-Dale IWTX-4646BE-50 comes with high-saturation powdered iron that is not affected by permanent locating magnets.