The power of a booster and the versatility of a buffer all in one pedal.
In buffer mode, the Reactive provides the best interface between your instrument and your effects chain. There will be no signal amplification but the low-impedance output will avoid tone deterioration and improve “responsiveness” of your guitar or bass due to the length of connecting cables among several effects. The Reactive is helpful, or essential, even between instrument and amplifier/mixer, especially when the cable is longer than 5 meters.
It is better to use a shorter cable from instrument to Reactive and a cable with the needed length from pedal output to amp. Low impedance transmission drastically decreases noise and buzz and also makes a low quality cable less dangerous for your sound.It is strongly recommended to use it in buffer mode when the chain effect is formed by true bypass pedals.
Do you need gain without affecting your instrument tone? Do you want more volume during your solos? Just select the “boost mode” and adjust the gain to the desired level by turning the knob. You can adjust the gain from 3 to about 30 dB.At the highest Gain level, the booster will produce a slight saturation which has the typical character of a tube overdrive.
For more details see the manufacturers website here