This unit is designed to be used for connecting to the end or return of the amplifier and lowering the volume. If the amplifier has a loop on/off SW, please turn it on and use. Please use 100% if the amplifier has a loop mix knob. When connecting an effector other than this device to a loop, please connect this device to the end of the effector. It can also be used to connect between pedal board and amplifier. We also sell them on other sites. Please note that there may be cases where it is sold out even if you put it in a shopping cart. ■Type: Attenator■Features: Passive design, no power supply or battery required.