The Behringer Ultra-DI Pro DI4000 4-channel Active DI Box gives you four top-shelf DI channels in one rack space. Direct Injection (DI) boxes, of course, let you plug guitars and basses, keyboards, etc. directly into your board. For impedance matching and signal integrity, they're indispensable. The DI4000 is a DI on steroids. With its active circuitry, it sports buffered inputs that won't pollute your signal (as passive DIs can). Boasting a bevy of boost/attenuation, groundlift, and connectivity options, Behringer's Ultra-DI Pro DI4000 is your audio Swiss Army Knife.