This is a 45W Passive attenuator for guitar amplifiers made by Dr.Z in Cleveland, Ohio. Premium quality attenuator (N.B. not a load box...this cuts power from the amplifier to the speaker; it doesn't replace the need for a speaker) made by a legendary manufacturer - design input from Trainwreck legend Ken Fischer. This is the Stand Alone version.
In excellent condition (as pictured), and in the original box. The box has a few marks to it, but nothing major. Excellent product that Z sadly cannot make anymore due to the big resistors being discontinued.