Internal Gain Trim Pots ? I designed these in order to give each player more control over their tone as well as make the modules more versatile over all. Reason being; There are many variables that weigh into the tone such as guitars, pickups, pickup height, etc so if a player wanted more/less gain, low end, etc they would have to ship the module back so we could customize it. You can now adjust the trim pot and to dial in exactly what you are looking for. In addition to changing gain the trim pots are also frequency dependant and effect how the tone feels.
Some trim pots are set to what the Mod calls for though I also dial in the trim pots based on the guitars/pickups that each customer is using. There are a plethora of possibilities once you start experimenting with them and I usually mark the pots so one can always get back to the same settings I dialed in. I also include these with Custom Mods as well.
I hope this helps and as always questions are more than welcome as they help me to better meet your needs.
All the best!
Trace