In the words of Boss:

Passionately designed by the master engineers at BOSS in Japan, the Waza Craft BD-2W delivers a premium stomp experience that fans of customized pedal tone will love. Crafted with an ear for highly refined sound, the BD-2W takes the classic Blues Driver grit to a new level with all-discrete analog circuitry. Standard mode captures the classic BD-2 tone while Custom mode delivers new body and sustain.