The Radial ProDI is a passive, transformer-based direct box built to connect high-output instruments such as active basses, acoustic guitars with onboard preamps and digital keyboards to a mixing desk or PA. It converts the unbalanced 1/4" instrument signal to a balanced, low-impedance XLR output that can run long cable distances to front of house without picking up noise, while the 1/4" thru jack sends the untouched signal on to the player's own amplifier. At its heart is a custom-wound Radial transformer (Eclipse ET-DB2, 12:1) with a 140k Ohm input impedance and an internal MuMETAL shield, so it copes with big transients without distortion. A -15 dB pad and a ground-lift switch deal with hot sources and ground-loop hum. It needs no phantom power. The box is housed in a 14-gauge steel chassis and outer shell, measures 108 x 70 x 44 mm and weighs 0.54 kg. Radial covers it with a transferable 3-year warranty. Radial part number R800 1100 00.