1981 Inventions describes the LVL as a "professional low-gain device," and apparently it is a brand new circuit design that does not rely on a classic pedal archetype (such as the Klon, Tube Screamer, etc.) The LVL straddles the world between a preamp and a low-gain overdrive. Using light clipping and and op-amp grind, the LVL delivers tones from a heavy boost to medium overdrive. But that's just when you use it on its own—when you combine it with other pedals, the LVL could be the drive-stacker's absolute dream!
The controls are simple: "VOL" is output volume, and "LVL" functions essentially as a gain control. As you explore the tones in the pedal, the LVL control in particular has a wide range, and each position responds differently to your picking attack, too. As you experiment with different pickups and guitars, you'll discover a much wider range of sounds than you might expect from just two knobs.
Relative to other overdrive pedals, the LVL retains note definition nicely as you crank up the gain. Even when stacked with other pedals, there's still a strong since of definition and clarity. When stacked, the LVL seems to highlight the unique characteristics of other drive pedals. Too cool!
This 2020s 1981 Inventions LVL is gently used and functions 100% as it should.