2VCA contains two separate VCA (voltage controlled amplifiers); the classic module to shape the volume of a sound that is fed to IN by a control voltage, e.g. from an ENV to the CV input.
A switch determines the operation mode (DC/CV or audio), choosing the right position can reduce/avoid pop's with short attack envelopes.
An additional knob for each VCA attenuates the level, if necessary.
You can find more information about this module on the AE Modular Wiki.
(Price without VAT; for buyers inside the EU 19% VAT will be added to the shown price = 29,75€)