Minty GD Descender (no cables to mess with, just a simple knob on the post). Probably used for 20 mud-free SoCal rides, clean and not a mark on it except for a bit of scratched anodizing at the very bottom of the post from the seat tube. Current generation version (bulletproof), with the three anti-twist keys and solid upper shaft. (Older versions have only two keys and a hollow upper shaft.)

Normally sells for $250 plus shipping.

30.9mm (no shim)
5" travel
3-position version (full up, 2.5" down, 5" down)
400mm length

185 shipped to lower 48. Will add photos in the next few days.