Two Rock Bloomfield Drive 40/20W Head Black Bronco w/ Black Matrix Grill2024 Two Rock Bloomfield Drive 40 20W Head Black Bronco w Black Matrix Grill With footswitch and certificate of authenticity The Two Rock Bloomfield Drive 40 20 is their latest two channel, cascading gain style amp that revisits their popular Custom Reverb Signature platform. The Bloomfield Drive utilizes Two Rock's new proprietary output transformers that allow for 4 x 6V6 power tubes switchable from 40 watts full output to a 20 watts for more gain