Check out the demo video (make sure you can listen in STEREO)!

Description from Cusack Music:

The latest version of the world's first Tap-Tempo tremolo - the V4.

• Fully Analog 
• 24 waveforms
• Full stereo signal path
• Digital presets, 4 banks with two presets each
• Tap-Tempo
• Speed brake up and down speed controls
• Right output phase control
• Dedicated Exp./Tap/Sync input (Auto-detects input type)
• Option knob for tempo divide, fade in control and more
• Basic Depth, Level and Rate controls
• Configurable expression
• Live mode and Preset mode

V4 features dedicated, directional Brake footswitches. 

Backstory:
The world's first tap-tempo tremolo pedal, the Tap-A-Whirl, had to be discontinued due to part availability. The particular obsolete vactrol we used was the heart of the pedal. We searched far and wide for a replacement, to no avail. We had to work with part vendors to produce a special component that could meet our specifications. Now, after much ado, the Tap-A-Whirl is back. The new component allows for even faster tempos than the original Tap-A-Whirl. While we were at it, we added some serious upgrades to the user interface and feature set. The Tap-A-Whirl V4 is the most advanced tap-tempo tremolo pedal known to man.

24 Waveforms

3 Banks A,B,C

We've included the most common waveforms, as well as some truely unique and bizarre ones.

The odd time signatures in bank C are especially useful.  Each waveform is very interactive with the tempo divide feature.

Preset System:
We took our digital preset system from the Resound and integrated it into the Tap-A-Whirl, keeping the audio path fully analog. Saving and recalling presets is now a breeze. With a few clicks of the feet, a new preset is stored.

POWER
• Standard 9v DC, center negative power supply
• Current draw ~22mA

OTHER SPECS
• Buffered bypass based on Cusack More Louder
• 4.75” x 3.85” x 2.25” (L x D x H)