FIG. 1 is a bottom plan view of a back cover for a handset showing my new design in the environment of a handset;

FIG. 2 is a right side view thereof;

FIG. 3 is a rear view thereof;

FIG. 4 is a left side view thereof;

FIG. 5 is a top plan view thereof;

FIG. 6 is a first perspective rear view thereof;

FIG. 7 is a bottom plan view of a back cover of a handset showing my new design illustrating a back cover in isolation;

FIG. 8 is a right side view thereof;

FIG. 9 is a rear view thereof;

FIG. 10 is a left side view thereof;

FIG. 11 is a top plan view thereof;

FIG. 12 is a first perspective front view thereof; and

FIG. 13 is a second perspective front view thereof.

The broken line showing of the inside surfaces and extending tabs in FIGS. 7, 8, and 10-13 and of the remainder of the headset shown in FIGS. 1 -6 is for illustrative purposes only and forms no part of the claimed design.