Please note this is an OE Shock removed from a new bike, unused with warranty.
The third generation of the Fox FLOAT X2 gets a ground up redesign. The addition of Variable Valve Control to the high speed rebound circuit required a new chassis, so Fox thought "if we have to redesign the shock, lets make everything better". Variable Valve Control started life in the GRIP2 damper and allows riders to change the stiffness of the high speed rebound valve without changing the total amount of oil that can flow resulting in a shock that can recover from big hits better while having finer control over the flow of oil.
This is matched with a new higher flowing main piston to enable the higher shock speeds produced from big hits to be better controlled without having to restrict oil volume which could add harshness. When combined with a new progressive bottom out bumper, new air spring design and a more significant tuning range for the High Speed Compression adjuster thanks to that improved control of oil, tuning how the shock responds to big hits is more easily achieved with just a 6mm Allen key.
Trail and Enduro riders have to go up mountains as well and the move to VVC allowed the 2-position climb switch to be placed on a separate circuit, meaning the "lockout" is noticeably firmer as it no longer has any effect on the open mode tune.
Reliability, performance, service-ability, and the ultimate in external adjustability. The best air shock money can buy - Without any doubt.