The Behringer 911 Envelope Generator, part of their series of vintage Moog-inspired Eurorack modules, is a four-stage envelope generator, perfect for controlling VCAs and filters. The four-stage envelope features controls for attack, decay, and release time, plus sustain level, creating your standard ADSR envelope. The range of times per stage is wide and goes from 2ms all the way up to 10 seconds. This allows for everything from super snappy envelopes to longer envelopes that develop and shape parameters over time.