In the words of Keeley Effects:

Featuring Manhattan-style compression, the Compressor Mini intuitively and automatically delivers the perfect blend of dynamic and compressed guitar signal. This is how the Compressor Mini retains all of the subtlety and dynamics in your playing, making it effortless to play and sound your best. An all-new transient release time is set to make both single coils or humbuckers sound lively and expressive. The new automatic tone recovery circuit ensures crystal clear highs, even with high compression settings. The Compressor Minis pre-amp tone is legendary; pushing both pedals and amplifiers to their greatest potential. With any style of guitar, playing live or at the recording desk, the Compressor Mini is your secret weapon. Weve done the math for you, this is the new calculus for great tone.