They say:

With the TU-3W, BOSS brings Waza Craft mojo to the world’s leading stompbox tuner. At its core, the TU-3W provides rock-solid tuning equivalent to the industry-standard TU-3. In true Waza tradition, the pedal’s benchmark functionality is further enhanced with BOSS skill and craftsmanship. Pure, uncolored signal transfer is essential for a tuner, and the TU-3W features redesigned circuitry with selectable buffered or true-bypass operation and the most transparent audio pass-through possible. Packing high-end performance for discriminating players, the TU-3W delivers a premium pedal experience only available from BOSS.