Prices are per caliper
Vesrah ZZ compound pads have a very aggressive initial bite at low lever pressures when compared to the SS and even moreso the XX compounds, this gives instant high force braking at the touch of the lever.
The ZZ compound stands at the top of tree when it comes to initial bite, but a lower heat endurance rating than the SS compound, and less easy to modulate small levels of braking force than the XX compound.
The ZZ compound is particularly good on fast flowing tracks where there are long sections that cool the brakes off, but then lead into high braking force zones