Check the listing for details. Pyle Premium Direct Injection Audio Box - Passive DI Unit Hum Eliminator ..... Color: Black, Condition: New. Listed at 17.91 USD. BRAND NEW¼ “ DEVICE CONNECTOR: Provides a variety of DI solutions with its ¼ inch device connector and detachable AC power cord for live sound recording applications. It allows you to easily connect keyboards, guitars & outboard signal processorsPROVIDES CLEAN AUDIO: Useful for connecting unbalanced signals from sources submixers, effects processors & keyboards to a main PA or recording mixer. This impedance transformer also has buzz & hum cancellation abilityEASILY CONNECTS INSTRUMENTS: Getting the signal of a musical instrument to the PA system is easier with this direct box. Just connect the electric bass, guitar, keyboard or other processors to the ground lift adapter & enjoy pure & clean audioVERSATILE DIRECT BOX: Aside from music instruments, the DI unit can also be connected to the line output of a boom box or consumer stereo system if you want to sample old records. The hum eliminator is used for connecting unbalanced devices as well.