Here’s what Boss say:
The all-analog PW-3 delivers pro wah tones in a rugged, space-saving design that conserves precious real estate on your pedalboard. Newly developed by BOSS, the PW-3’s Rich mode has a uniquely full wah voice that retains the low-end definition and fullness lost with typical wah circuits. Want a more traditional tone? Just flip the rear-panel switch to Vintage mode for that classic wah vibe.
Unlike other pedals that sacrifice feel and functionality when trimmed down in size, the PW-3 strikes the perfect balance between practicality and playability. Its die-cast aluminum chassis is solid and substantial underfoot, and the long, smooth pedal action is highly responsive and feels great. Another issue with downsized pedals is that it’s hard to see when the effect is on or off, because your foot blocks the view. The PW-3 solves this with status LEDs on each side of the pedal, making it much easier to see when the wah is activated.