The Blood Donor combines the best elements of a Tone Bender MKII and a Pro Co Rat

Like the original Katzenkönig, the Blood Donor combines the best elements of a Tone
Bender MKII and a Pro Co Rat. Namely, a supercharged silicon Bender circuit and the
output section of a Rat. By tweaking the knobs, you can cop everything from a robust,
chimy clean tone to full-on high-gain meltdown. This comes at the expense of . . . nothing.
You can use any stringed instrument, synthesizer or drum machine all to equal effect with
only minor tweaking involved to find the sweet spots.

https://cdn.shopify.com/s/files/1/0370/1873/0628/files/blood-donor-manual.pdf?v=1588317213