With this PCB you can build a clone of the analogman sunface with germanium transistors. 

The Sunface is different from the usual fuzz face in a couple of areas: A smaller input capacitor and a lower output potentiometer make a less bassy fuzz overall. These also have a trim pot for you to add a little resistance to the input - this enables the fuzz to play with humbuckers and high output pickups better than a bog standard fuzz. 

This PCB features a charge pump - this converts the incoming 9V +ve to 9V -ve as required by the vast majority of germanium transistors. This feature means you can daisy chain this fuzz with more modern effects (i.e anything from around 1970's onwards!.).

The extra control is called the "Sundial" by analogman. It is basically a bias control for the second transistor allowing you to dial in rougher more vintage type tones (used to good effect by Eric Johnson) or smoother more Hendrixy sounds. With the germanium version is also allows you to dial in the sweet spot as germaniums are sensitive to the ambient temperatures.

The board allows for reverse polarity protection and also some mains filtering if you want to run this from a power supply rather than a 9V battery.