The Sennheiser SK-XSW-B (article 507323) is the bodypack transmitter from the XS Wireless 1 and XS Wireless 2 ranges, sold on its own to add a performer or replace a unit in an existing system. It operates in the B range of 614 to 638 MHz using wideband FM, so it must be paired with an XSW receiver on the same B range, and users should confirm this band is permitted locally. It clips to a belt or waistband and accepts lavalier, headset or instrument cables through a 3.5 mm jack socket. Output is 10 mW, audio response is 50 Hz to 16 kHz on line and 80 Hz to 16 kHz on mic, and input sensitivity is adjustable from 0 to -30 dB in 10 dB steps. It runs on two AA batteries for about ten hours, and the rugged ABS housing measures roughly 71 x 96 x 28 mm and weighs about 95 g. Microphone not included.