Korpa 
The 535Q Cry Baby Multi-Wah features a six-position Range Selector, a Variable Q control, and a switchable boost circuit so you can dial in the ultimate wah tone.
This pedal can be powered by a 9-volt battery, a Dunlop ECB003 9-volt adapter, or the DC Brick™, Iso-Brick™, and Mini Iso-Brick™ power supplies (not included).
The Long Story
Dunlop engineers worked closely with the world's top guitar players to design the 535Q Cry Baby Multi-Wah, a pedal that allows you to fine-tune your wah sound and make it your own.
This is the Swiss Army knife of wah pedals. Its six-position Range Selector control allows you to choose from six different frequency ranges, each position based on the unique tonal characteristics of our most prized wah specimens. The Variable Q control allows you to take the 535Q's response from narrow and sharp to broad and subtle with the twist of a control. Once you've got your sound, make sure it gets heard with the switchable boost—adjustable up to +18dB—that can create endless sustain on any note.
The 535Q provides control over the most important wah parameters so you can create your ultimate wah tone.