This is TTC Silent stem in TTC black switch non-silent housing.
The interesting thing about these switches is they make a clack sound on the downstroke but the upstroke is silenced. They are kind of a “semi-silenced“ hybrid.
Springs are 78g Sprit
Switches are lubed with Tribosys 3204
Keyboard is a dampened K-type.
Stabilizers are modified to reduce upstroke noise.