Carl Martin Hot Drive'n Boost MKII has been carefully designed to imitate the sound of a good old-fashioned distording Tube-Amp. It is similar to the Hot Drive'n Boost but has a rougher and deeper sound. With the BOOST feature the Hot Drive'n Boost MKII is a ''TWO In ONE'' pedal. That allows you to get that extra ''kick'' (up to 20db) for solos to really stand out. The Hot Drive'n Boost MKII has a built in regulated (+-12V) power supply. This enables us to design circuitry of the highest quality with maximum headroom. The low output impedance insures a low noise connection and a really great tube amp sound!