FIG. 1 is a bottom plan view of a back cover detail for a handset showing our new design;

FIG. 2 is a right side view thereof;

FIG. 3 is a left side view thereof;

FIG. 4 is a top plan view thereof;

FIG. 5 is a rear elevational view thereof; and,

FIG. 6 is a top, rear and right side perspective view thereof.

The dotted lines showing the outline of a telephone handset are for illustration purposes only and forms no part of the claimed invention.