It is for upgrading the A.3 Justifier MK II To adjusted. Maybe have more uses, but thats what I know about.
The upgrades needed for it are:
50 generic nano adjusters
10 tuning nano adjuster w04
75 gec spur gears 4K
2 jester D4 (L) full condition.
And yes, the mu on these things have sky rocketed because of this.