What’s in the Box

I recently came across the JHS Little Black Amp Box.

It’s a little box that goes in an amp’s effects loop and promises cranked tube tone at lower volume. From what I can tell it’s just a box with a volume knob in it. So, basically, it would act as a master volume. If your amp already has a master volume it’s probably not needed but if you have an effects loop and no master volume this could be useful.