Difficult to just know what you mean from what you said?
But I’ll hazard a guess, the inputs 1 and 2 on the back panel are whats called combo connectors, that is you can connect a XLR for mic input or using the hole in the middle a line input or if you switch the high impedance switch on the front it becomes an instrument input.
I can’t imagine what you are referring to unless it’s the two little gain knobs on the left, top of the interface. They probably will give you approximately 4db of gain when turned to max.