From Spaceman Effects:

About Mercury IV

We are excited to present the Mercury IV, a unique Germanium Harmonic Boost pedal. Eight years ago, we introduced the Mercury III and we have updated the original circuit for a new spin on that classic pedal.

The Mercury IV is a dynamic tone enhancer, created to bring out additional harmonic character from instruments and amplifiers. The pedal features a unique, discrete analog circuit, with a meticulously selected vintage germanium transistor at its heart.

The Boost control of the Mercury IV offers a staggering 35 dB of gain, with nine (9) tone-shaping options via two toggle switches, to gently or aggressively boost tube amplifiers. The real magic however, resides in the Harmonics control; bringing more dimension and life to ones’ tone. Subtle sparkle, complex textures, and octave-like overtones can all be found here. With a sound and response like hot tubes on the edge of breakup, these even-order harmonics are independently generated, giving you full control over the mix.

The Mercury IV is completely hand-soldered and handmade in Portland Oregon to the highest degree of quality possible. These are truly artisan-crafted tone devices, sparing no detail within or without. The Mercury IV utilizes true-bypass switching via the heaviest duty mechanical footswitch available, while your tone is transferred via quality open-frame Switchcraft jacks. Open one up and you’ll see an unparalleled display of craftsmanship; with immaculate hand-soldered PCB, detailed military-spec wiring, and custom Spaceman heavy-duty battery connector. On top of the cast aluminum enclosure sits a durable, engraved vinyl faceplate and jewel indicator light. This pedal is truly built to last a lifetime.

Each pedal number is hand-hammered on the nameplate, stating its limited availability and each is also signed and numbered on the inside.