Aah, thought you were joking..
Klein&Hummel are from Germany - the "Stuttgart" on the front plate.
And they are very, very German
The basis for the UE100 was the idea to develop a maximally precise equalizer, and as inductor core material is notoriously temperature sensitive, they designed it around only capacitors as frequency-determining, switches controlling only resistors.
Wait, you may say - capacitors are temp dependent too..
..yes but - everywhere in this beast where you have a frequency determining capacitor, it consists of two paralleled precision capacitors: One with a positive and one with a similar negative temperature coefficient.. Pic related, it's the dual-styrene-like ones covered in red tape..
In my opinion over-designed in a way that only very obsessive-compulsive German engineers can be allowed to. Sometimes wonder if a bit of medication at the right time could have saved some pain here.
/Jakob E.