Sennheiser EWD1-CI1 instrument Onstage, you want range, audio quality, and ease-of-use from your wireless system. Sennheiser's EW D1 2.4GHz digital systems deliver it all, in addition to amazing value. Perfect for applications that require up to eight systems, EW D1 wireless rocks Sennheiser's Automatic Frequency Management, which continuously scans for interference and changes frequencies on the fly if necessary. D1 systems detect each other and work together to assign and manage frequencies. The EW D1 instrument set includes a receiver, a bodypack transmitter, and CI1 instrument cable. The last thing you need when you're performing is hassles from your wireless system. Go hassle-free, with Sennheiser's EW D1 digital wireless.