The Doepfer A-145 is a low frequency oscillator (LFO) module for the Eurorack A-100 system. Featuring five waveform choices: sawtooth, inverted sawtooth, triangle, sine and square waves, the A-145 can be used to modulate a whole host of modules such as oscillators, filters and amplifiers. There is a control for sweeping through the frequency rate as well as a switch to select three frequency ranges, from quite slow to relatively high (4-5 kHz). A perfect module for the starter rack.