The Sennheiser XSW-D Portable Base Set is a small 2.4 GHz digital wireless system for getting a lavalier or other 3.5 mm microphone signal into a DSLR, mirrorless camera or camcorder without a cable. It contains a 3.5 mm mini-jack transmitter and a 3.5 mm mini-jack receiver that pair instantly with one touch, a belt clip for the transmitter, a hot shoe mount for the receiver, a coiled 3.5 mm cable and a USB charging cable. The licence-free 2.4 GHz band works worldwide, range is up to 75 m in optimal conditions, and latency is under 4 ms. Both units have built-in lithium-ion batteries lasting up to 5 hours and recharging in about 3 hours. Audio frequency response is 80 - 18,000 Hz and signal-to-noise ratio at least 106 dB. Multiple transmitters can be linked to one receiver and either unit can mute. A clip-on microphone is not included - pair it with a Sennheiser ME 2 or similar 3.5 mm lavalier.