This Schaffer Replica Storm tribute is a perfect Boost-Gain-Limiter Swiss knife pedal.
Its including up to 30dB of gain, a classic mid-hump boost AND an opto-isolator limiter circuit to give a nice compressed attack. Level control the Pre-circuit Gain, Boost is the post circuit gain, limiter is the compression level.
You'll notice little compression when using a lot of pre-gain (Level).
Power Consumption : 10mA
Voltage : 9Vdc center negative
Video of the prototype unit :