TRP mechanical discs (calipers) are one of the few (if only ?) mechanical disc brake systems that feature two piston movement
they perform better than most of the other mechanical systems (if not all) and are easy to set up and adjust ; 3mm hex adjusts pads in and out
still not as good as a quality hydraulic system - but still fairly good
pic of a TRP Spyre SLC caliper above
I have these on my ETap Tarmac. They work quite well, I am pleased with them.