The ornamental design for knife handle, as shown and described.
FIG. 1 is a perspective view of one side and a top of the knife handle.
FIG. 2 is a perspective view of the other side and a bottom of the knife handle.
FIG. 3 is a side elevation view of the other side of the knife handle.
FIG. 4 is a side elevation view of the one side of the knife handle.
FIG. 5 is a top plan view of the knife handle.
FIG. 6 is a bottom plan view of the knife handle.
FIG. 7 is a back elevation view of the knife handle; and,
FIG. 8 is a front elevation view of the knife handle.
The broken line showing of the knife bade is provided for purposes of environment and forms no part of the claimed design. The portions of the knife handle that are depicted by broken lines such as the liner lock and bolts, form no part of the claimed design.