Compounds for alloy wheels
White writing on pad indicates pad is compatible with aluminum wheels
Compounds for alloy wheels may be different colors including black, green and blue, but all have white writing on the side of the pad.
Compounds for carbon wheels
Yellow compound or writing on pad indicates pad is compatible with carbon wheels
SwissStop's brake pads for carbon wheels can be identified by the yellow compound, in the case of the Yellow King, or yellow writing on the side of the pad in the case of the Black Prince.