The Doepfer A-119 is an external input and envelope follower module for the Eurorack A-100 system. A great way to get audio signals integrated into your modular rack, the A-119 is also great at giving you those classic auto-wah sounds. This is a really useful module for the beginner due to its dual functionality. The large jack input on the front also means you can plug a guitar or bass directly in. There are controls for the pre amp gain and threshold level for the auto wah.