Module A-145-4 is a simple quad LFO. Virtually every system requires a few simple LFOs for modulation purposes. The module contains four simple LFOs with the waveforms triangle and rectangle. A dual color LED (red = positive / yellow = negative output voltage) indicates the triangle output of each LFO. 50Hz ... 0.04Hz (about 20 seconds, jumper removed) and about 2Hz ... 0.002 (about 8 minutes, jumper installed).