The Sennheiser EW-D Evolution Wireless Digital System with SK Receiver and Bodypack Transmitter is a versatile and feature-rich digital wireless system for performers who sing, speak or play instruments. The EW-D digital system allows for seamless product pairing and management via the EW-D Smart Assist App. The convenient Mobile App features a streamlined, automated setup that creates reliable connections with minimal time and effort. Up to 2,240 selectable frequencies support up to 24 wireless systems per frequency range and preserves every detail of even the most dynamic performances up to 134dB. With a metal housing, the robust bodypack transmitter suits perfectly for daily use on stage. The Evolution Wireless Digital System delivers up to 12 hours of operation on the included lithium Ion battery pack or up to 8 hours of operation with AA batteries.