There are surprisingly few FM modules on the market. Even though it has FM functions, there are only a limited number of modules that can produce beautiful musical overtones. (Musical: The modulation frequency is an integral multiple of the carrier frequency)

Power supply: 29mA

2 Operator (carrier, modulator)
knob1: Carrier frequency
knob2: Modulation frequency
knob3: Modulation amplitude
freq CV: Modulation frequency CV
level CV: Modulation amplitude CV
V / oct (10bit, 5Vp-p)
Output is 4Vp-p.

More info:
DIY and docs: Github

Organise your case: ModularGrid