Erica Synths Acidbox III is an analog effect device primarily for synthesizers, but also for many other instruments. It is based on the core of the famous Polivok VCF with its unique audio signal overdrive circuit, a built-in LFO and envelope follower in a compact aluminium housing. The difference to the original Polivoks VCF is that it is available in the Acidbox III as a stereo version. With its adjustable input level, it works with various sound sources such as guitars, synthesizers, groove boxes and modular synthesizers. The configurable control input allows the connection of a bypass foot switch, an expression pedal, an external control voltage or an LFO synchronization trigger.