Korpa 
Valeton Surge EP-2 Volume/Expression Pedal
The Valeton Surge EP-2 is a compact passive Volume/Expression pedal for guitar, bass, and other electronic musical instruments. It requires no battery or power adapter and automatically detects whether it is connected as a volume or expression pedal.
Features
Compact, lightweight housing
Passive 2-in-1 Volume/Expression pedal
Automatic detection of Volume or Expression mode
No battery or power adapter required
Compatible with guitar, bass, and a wide range of electronic musical instruments
Smooth, precise pedal response for volume and expression control