This is the Behringer ADI21, a multi-functional DI box for acoustic guitars. In November 2025, it seemed to be a popular effector, with few new stocks available, so I purchased it from Mercari because I couldn't get it. It converts the output from an acoustic guitar to DI (reducing degradation and attenuation) and sends it to a PA mixer. However, when I used it, I felt that the EQ function as a preamp worked moderately well, and it seems to suppress the howling peculiar to hollow-body instruments depending on the settings. It mellows the harshness of the piezo pickup sound. It seems that some people use it not only for acoustic guitars but also for ukuleles. It has a compact body, but it's heavy inside, giving a sense of security that it won't fly away even if kicked. *Price includes commission and shipping - Model Name: V-Tone Acoustic ADI21 - Functions: Acoustic Modeler, Driver, DI - Controls: Treble, Mid, Bass, Level, Mid Frequency, Blend - Connectors: Input, Output, PAD, GND LIFT switch #Behringer #di #acousticguitar #effector #eq #adi21 #adi #ukulele #guitar #preamp #Behringer