Dunlop 535Q Cry Baby Multi-Wah Guitar Effects Pedal Provides control over the most important wah parameters Ability to select frequency center and range of the effect Features adjustable, switchable boost Power: Dunlop ECB003 AC Adapter or Single 9 volt battery Offers six new guitar wah ranges, "Q" dial allows you to shape your wah from a narrow, sharp wah to a broad, subtle wah. Features a variable boost from 0 to +26 dB Hard wire on/off switch