This is an equalizer that is also popular with bassists. The box in the image and the English manual are included. The following is a quote from another seller's product description: Setting the HPF around 100 Hz and applying +5 dB of resonance, and setting the LPF around 5 kHz, you can get a convincing cabinet sim. Adding the mid EQ will add more nuance. By experimenting with various frequencies and resonance, you can obtain a wide variety of speaker profiles. Setting the HPF to the fundamental frequency or first overtone of the open E string (or B string) will tighten the low end and make it more focused. Adding resonance will increase the punch. Setting the HPF to a resonant low frequency (30-60Hz) will emphasize the octave-down effect while simultaneously removing unwanted sub-frequencies. Setting the LPF to 2k to 4k and adding resonance will give an aggressive attack, giving presence and character to the tone without the high end ringing out. Setting the LPF to 10k and applying light resonance will give an airy Hi-Fi effect without boosting all the high frequencies. The filter resonance is from -3db to +15db, and the slope is -12db/octave. The input impedance is 1MΩ, and the output impedance is 100Ω. The DC power supply uses a standard Boss-style connector with a center-negative polarity. It supports 9 to 24 volts. 9 volts is sufficient for most applications, but when using line-level signals, you should use at least 12 volts to ensure sufficient headroom. The current consumption is approximately 20mA. Effect type... Equalizer