First generation Leda RACE , double adjustable gas again uses a remote canister as above but has separate bump (compression) and rebound (extension) adjustment. The unit can be tuned to the finest degree, with an amazing 576 different combinations. Used by rally teams and circuit drivers who need the ultimate tunable suspension.
These have been 100% rebuilt and have never been used since. Rebuild was last year.
These shocks go for about $4K new.

$2000