Available as an assembled Module and as a DIY project.
No info about availability.
Low Frequency Oscillator
This is a versatile yet easy to use voltage controlled low frequency oscillator module that can also be used as an audio VCO over a useful range. The oscillator is based on a triangle core, but sinusoid, sawtooth, ramp, and square outputs are simultaneously available. A hard sync input is available to reset the waveforms to a fixed point.
The module features two CV inputs: one frequency (1V/octave) and one frequency modulation (FM) input. The FM input is controlled by an attenuverter. A tricolour LED indicates the output status. The VC-LFO has an operating range of lower than 0.002Hz (one cycle every eight minutes) to over 14kHz from the front panel controls. The range can be extended with external CV inputs. The maximum frequency of the VC-LFO is well over 25kHz. When used as an audio rate VCO the usable range that conforms to 1V/octave (to +/-2cents) is over six octaves from approximately 32Hz to 2kHz.
Range of Frequency control: 17 octaves
Range of Fine Frequency control: 6 octaves
Sync input requires a fast rising gate exceeding 4V when active, or at least 2V peak pulse or sawtooth waveform.
These merchants probably sell this module. Huh?