Radial Engineering HDI DI Box w/ Color Control & Opto CompressorThe Radial Engineering HDI is a direct box designed to give you the colorful tone you want as quickly as possible. Use it on passive or active electric basses, electric guitars, or any mono instrument you wish to inject directly into the mixing console or house PA. The HDI offers some of the connections you'd typically find on a DI box, such as a 1 4" to XLR I O path with a 1 4" thru jack for outputing unaffected sound to an onstage amplifier.