Psycho Circuitry describes MicroXFORMer+ as a flexible transformer saturation/distortion. This is what they have to say about it...
Focusing on fine-tuning the distortion caused from hysteresis, you have 3 controls for shaping the character of the distortion. Hysteresis Character lets you adjust from "brittle" to "spongey", Hysteresis Amount controls the level and Contour shapes the clipping onset to preserve more natural transients. 4 transformer types to choose from.
There's also a free MicroXFORMer version available that provides the hysteresis character control and 2 transformer types
Pricing and Availability:
MicroXFORMer+: On offer at $19 (Regular price: $29)
MicroXFORMer: Free
More information:
Older Music Machines & the People Who Still Use Them