It is a low frequency oscillator (LFO) with an adjustable frequency range. The output level can be changed and blended between triangle and square signal.
See https://polykit.rocks/lfo for technical details and assembly.
Disclaimer: Kits or PCBs like this require a certain experience to assemble. A set of tools and basic understanding of electronics and components are required. All kits/PCBs are sold at the purchasers risk. Used or assembled kits can't be returned.
