FIG. 1 is an upper perspective front view of the new design applied to the key matrix of a handset;

FIG. 2 is a front view thereof;

FIG. 3 is a right side view thereof;

FIG. 4 is a bottom view thereof; and,

FIG. 5 is a left side view thereof.

The portion of the handset shown in broken lines is for illustrative purposes only and forms no part of the claimed design.