This pedal is a faithful recreation of the original TS-808 Tube Screamer circuit and features the JRC4558D op-amp. Its overdrive circuit provides the same tone as a vintage '808, noted to provide tube like overdrive effects while retaining the guitars original tone.
The internal thumbwheel, which can be seen just at the edge of the circuit board (once back cover is removed), will adjust the amount of bass frequency gain. The range is from stock TS to an approximately flat response. This allows you to adjust the amount of bottom to your personal taste.