Envelope Filter

Valeton Katfish Auto Wah, Coral series effect pedal for electric guitar & bass, fully controllable auto wah pedal with high thomann accurate and fast tracking, 100% analog, true bypass, solid aluminium chassis, controls: sense, freq, reso & decay, on/off switch with status LED, jack input & output, power consumption 12mA, requires 9V power supply (not included, optional #409939), dimensions:93mm (D) x 50mm (W) x 46.5mm (H), weight: 175g

https://www.thomann.de/gb/valeton_katfish_auto_wah.htm