Germanium Boost by amplifier maker Benson Amps. This is a clean booster using germanium transistors. It's recommended to use it as a preamp, leaving it on all the time. The exterior has some scratches, but is generally clean. Operation is also good. Includes box, instruction manual, etc. ~From the manufacturer's website~ The GERMANIUM BOOST is a clean booster using germanium transistors. Similar to the GERMANIUM FUZZ, it controls the voltage applied to the germanium transistors and warms them to the most suitable operating temperature. Therefore, it takes about 10 seconds for the bias to stabilize after startup, but it produces a stable sound without being affected by the surrounding temperature, which is a problem with germanium transistors. Sound Characteristics The input headroom has been widened to allow the germanium transistors to be sufficiently driven without unnecessary distortion, even with conventional guitar signals. In addition, by increasing the input impedance, the problem of "thin sound (loss of low frequencies)", which is a weakness of BJT transistors, has been solved. Also, it features a musical tone, and even at unity gain settings, it sounds smoother with finer details compared to the original sound. The unique compression feel cannot be obtained with a compressor. Boosting further drives the amplifier and simultaneously provides a thick sound with rich harmonics. It matches not only guitars but also basses, and its unique thickness and exquisite harmonics are one of a kind. It also works well with acoustic guitar pickups, bringing you closer to a warm, natural sound similar to the original sound. Note: Germanium transistors will stop passing sound when the temperature exceeds approximately 48.9°C (120°F). Please be careful on extremely hot stages, such as in the blazing sun.