This very nicely done demo video is for the Electro-Harmonix Riddle - an envelope filter fine-tuned for guitar frequency response.
In the video, Jack Conte does a great job of both demonstrating the range of the Riddle and exploring it within a musical context.
Here's the rundown on the Riddle's features:
- 80 Hz to 5 kHz frequency response tailored for guitar
- Optional expression pedal control
- Switch selectable analog distortion designed for guitar
- Start and Stop sweep control
- Low Pass, Band Pass, High Pass filter select
- Start and Stop for filter sweep and Q control
- Separate Dry and Effect outputs
- 9.6VDC 200mA power supply included