The Red Jasper “RJ-2V” features a sound resembling that of vintage tube amps, namely, smooth highs, punchy mids, full but tight lows, and natural compression feel. In general the sonic output of an overdrive unit in the lower registers varies with its gain setting and the type of guitar or amp/cabinet used. There would be many occasions where you wish to correct an excess or deficiency of the lower register components. The RJ-2V newly adds a mode switch to select from four modes of different low frequency characteristics (cut-off frequencies). With this you can adjust the lower register output to suit the characteristics of your guitar/amplifier.

Features

• Carefully chosen high reliability components.
• Passive type tone circuit (hi-cut) to minimize phase error in guitar signal.
• Mode switch to select low end frequency characteristics from four settings.
• Astoundingly excellent signal-to-noise ratio.
• Free The Tone’s original HTS (Holistic Tonal Solution) circuit is implemented. Unlike conventional buffer circuits, the HTS circuit attains both “sound” and “low noise”
  by performing impedance conversion while fully bringing out sound characteristics of the guitar. The HTS circuit prevents degradation of guitar timbre even when the effect is turned off.
• is no need to worry about phase reversal: the output signal is in the same phase as the input signal.

More info: https://www.freethetone.com.