I'm on vacation, shipping will be resumed after October 26th
This module is part of my Eurorack series. It is an envelope generator based on the 7555 timer integrated circuit. An envelope generator creates a control voltage that is usually used to shape a sound over time, e.g. in a voltage-controlled amplifier or filter. It sounds more natural than just turning a note on and off.
See https://polykit.rocks/adsr for technical details and assembly.