Wireless dual presenter system with two MX153 earset microphones combines professional-quality sound with reliable and user-friendly operation. The BLX188E wireless system consists of a BLX188E receiver, two BLX1 wireless transmitters, and two MX153 subminiature earset microphones. Designed for spoken word applications, this Shure system is equipped with a QuickScan function that locates the optimum frequency channel while CommShield technology prevents interference from RF devices and other digital bodypack transmitters. Frequency: 518-542 MHz