Quaife ATB Helical LSD differential for Focus ST as well as some Volvo models.

The description given below is applicable to the Focus ST:

Unlike a conventional plate-style limited slip differential, the Volvo S60 T5 front Quaife ATB Helical LSD differential relies on gears rather than clutch plates for its operation. That means it is much smoother in operation. The Volvo S60 T5 front Quaife ATB Helical LSD differential never locks harshly with a set pre-load of wheel slip across the driven axle, like a conventional LSD. Rather, the Volvo S60 T5 front Quaife ATB Helical LSD differential automatically biases the torque away from the spinning wheel across the axle, to a constantly varying degree, and never locks. The Volvo S60 T5 front Quaife ATB Helical LSD differential has many benefits over a standard open differential, including maximising traction and minimizing wheelspin, eliminating torque steer and snatching in front wheel drive cars compared to conventional LSD units, and a maintenance-free design which retains the standard oil lubrication. The Volvo S60 T5 front Quaife ATB Helical LSD differential is proven in circuit and drag racing, rallying and road use, and is produced from Corus steel billets, and is CAD designed and CNC machined, then inspected to ISO 9001 standards. With over 370 applications, the Quaife ATB Helical LSD differential is second to none. Accept no imitations! Quaife ATB Helical LSD differentials are used by Ford, General Motors and Daimler-Chrysler as original equipment. The Quaife ATB Helical LSD differential for Volvo S60 T5 front is also now subject to a lifetime warranty (subject to terms and conditions).  

Fitting price includes upgraded bearings as well as installation.