These cone springs will require Hilo adjustable suspension as they sit higher than the originals. Containg an anti fade property and shape which helps them going off during racing and giving hopefully a season of racing before replacement. 

These are manufactured by a highly technical company involed in rubber on Formula 1 cars.

If using these on 10" wheels with Hilos cut 3/4" off the end of the centre threaded bolt of the old type Hilo with a circlip as it will bottom out on the cone spring face and the car will sit high, for extremely lowered cars the hilo face will also need machining a few mm.
Sold singly and advise fitting in axle pairs.