The Sennheiser XSW IEM EK (A range, article 509156) covers 476 - 500 MHz. It is a UHF stereo bodypack receiver for the XS Wireless IEM in-ear monitoring system, used to add extra performers to an existing XS Wireless IEM setup: several receivers can listen to one transmitter. The lightweight bodypack clips to a belt or clothing, a status LED shows battery and link at a glance, and the backlit display only lights up when the locked settings menu is opened. From the menu the user can balance the mix, choose focus modes, add a 13 kHz EQ boost, enable a limiter to protect hearing, and pick preset channels or set frequencies manually. The standard 3.5 mm output drives the supplied IE 4 in-ear earphones or an IE PRO upgrade. Sennheiser quotes 45 Hz to 15 kHz response, 30 mW output (2 x 1.25 V at 16 ohms) and THD of 1 percent or less. It runs on two AA cells or rechargeables for about 6 hours, measures about 95 x 70 x 26 mm and weighs 110 g. Sennheiser covers it with a two-year warranty.