The Preamp is an immensely popular pedal and heralded as one of the best of all time. The MB (Mid Boost) edition takes the for original circuitry but also adds a Mids dial so that you essentially have a three band EQ. A very useful addition. The BLACK JUICE PREAMP takes the renowned -preamp to level. We've supplement the Pedal with a mid-boost control, adding more aggressive "bite" to your sound and up to +12dB of mid-treble boost. The MB version capable of covering all the tones that can be obtained with the standard Preamp by setting the mid control at 9 o'clock The Mid Dial is capable of adding up to 12 decibels of boost and if rolled off to around the nine o'clock mark it is supposed to be set in a neutral position, so that all of the tones of the for-original preamp can be had. Bass Boost - The bass boost knob which is capable of adding extra low end warmth to your signal, without ever becoming muddy. I am not sure for certain but I THINK it is capable of fifteen decibels of boost. Treble Boost - The treble boost knob which is capable of adding extra high end sprakle and to your signal, without ever becoming too brittle. CONTROLS: Gain control knob Mid Boost knob Volume knob Two Band EQ:Treble, Bass Gain - This is obviously the dial that controls the amount of juice, and there is quite a healthy amount on tap. Volume - There is a lot of volume available and a LOT of players tend to roll the gain nearly all of the way back and use the pedal as a boost, rather than an overdrive. Mid Boost - The mid boost is a tiny little knob and this is actually the only thing that really bugs me about the BBPreamp MB. It is quite difficult,especially for a man with fingers the size of mine, to get in and the knob without changing the settings on the four other knobs. Now obviously would have struggled to fit a full size fifth knob in there but I would much rather them have used a larger enclosure in order to fit a full size knob in. Perhaps it is just me, like I said it is the only flaw in the MBs my opinion. 4-MODE SELECTION KNOB:VOICING SWITCH True Bypass Switching AC Adapter:9VDC Negative Tips (Regulated recommended) Input Impedance:1M ohm Output Impedance:2K ohm Dimension(LxWxH):11.5x6.5x5CM Weight:320g Colour:Orange Material:aluminum alloy Package Contents: 1 * Guitar Bass Effect Pedal Only the above package content, other products are not included. Note: Light reflection and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.