This is the Behringer 2500 series OSCILLATOR MODULE 1004. An authentic reproduction of the original “System 2500” circuitry from the 70’s that can fit in a standard Eurorack case. The best part? It’s at a very affordable price. Mix the OSCILLATOR MODULE 1004 in with your existing rig or start your modular synth journey from here. The 1004 features discrete transistor circuitry to add vintage character and is equipped with coarse and fine frequency controls, frequency range switch, on/off switch, pulse width control, 3 modulation attenuators and best of all it features 3-position toggle switches for each waveform which can be set to inverted/off/non-inverted, all the enabled waveforms are mixed together to create complex waveform shapes and amazing sounds.