The Radial USB-Pro (part R800 1050 00) is a stereo USB digital-to-analogue converter and direct box for connecting a laptop to a professional sound system - for backing tracks on stage, audio-visual presentations, DJ work or transferring files in the studio. It is plug-and-play: no drivers are needed on Windows or macOS, where it simply appears as a sound card, and it converts audio at up to 24-bit/96 kHz. A pair of balanced XLR outputs feeds a mixer, mic preamp, PA or powered speaker, with an on-board level control, a mono-sum switch, ground lift switches and switchable isolation transformers to eliminate hum from ground loops. A 3.5 mm headphone output lets you check the signal. It is USB bus-powered (500 mA max). Note that the USB Type-B cable is sold separately. Response is 5 Hz - 40 kHz (30 Hz - 18 kHz with isolation); it measures 127 x 84 x 48 mm and weighs 0.68 kg.