The Tea Philter - A T-Filter Pedal Kit The Tea Philter pedal produces a fixed wah tone allowing you to lock it in without rocking the pedal back and forth. Every guitar/wah combination has a certain sweet spot that is perfect for lead and chord work. The Tea Philter lets you dial in everything from your favorite vocal mid-range tone to thick lows. Using point-to-point wiring and easy-to-follow instructions you can have a working fixed wah pedal in a matter of hours. The effect pedal operates on a 9V battery. For a longer lasting option, a 9-volt adapter can be purchased separately. The Godlyke 9-volt adapter (M-PAS-S) may be purchased separately to power your new pedal.