This abstraction is an audio-rate reverb effect. This effect adds reverb to an audio signal.
The abstraction has two versions, ControlRate and AudioRate. ControlRate abstractions are controlled by a control rate signal (like a slider object) and B is controlled by an audio rate signal (like an analog input).
Left inlet expects the audio signal that you want to be put through the reverb effect.
The second inlet expects a control or audio rate signal (depending on the abstraction) and controls the wet/dry balance of the effect.
Left outlet is the audio signal with the reverb effect applied.