Mission Expression Expression Pedal, Black with Spring Load Option - Andertons Music Co.
Amazon.com: Gamechanger Audio Bigsby Pedal Spring-loaded Polyphonic Pitch Shifter Effect Pedal with Fixed Center Position for Electric Guitar and Other Melodic Instruments : Musical Instruments
Made my own spring loaded wah pedal : r/guitarporn
Mission Engineering EP1-L6 Expression Pedal - Black, Spring-Loaded - Get Loud Music