The Shure GLXD14UK/SM31 Wireless Headset System is part of the Presenter Series from Shure. It features the GLXD1 pocket transmitter and SM31 FH headset and can run up to 8 systems parallel.  There is an automatic frequency set up and a display for remaining battery life in hours and minutes- an internal battery charger is included. There are fixed antennas on the front and XLR/jack outputs.  A fully charged battery will offer up to 16 hours performance time up to a 60 metre distance.