One knob, one understands quickly the operation ...
The volume is not super progressive, up to a quarter of the race there and nothing happens beyond it starts to boost frankly.
I use it between my pedals and amp for solo passages to increase the volume.
It adds a little gain to the input of the amp, I find it slightly dirty sound that is really not a problem in live use.
I use it for about two years.
Like its effectiveness and price.
If I were doing the same budget I will start again without hesitation.
With a little more money I'll look for a pedal instead of approaching Rangemaster)