The ornamental design for a removablecover for a device, as shown and described.
FIG. 1 is a front perspective view of a removable cover for a device of the present invention (the dashed lines are for illustrative purposes only and do not form part of the invention);
FIG. 2 is a front view of the removable cover of FIG. 1;
FIG. 3 is a back view of the removable cover of FIG. 1;
FIG. 4 is a side view of the removable cover of FIG. 1;
FIG. 5 is the other side view of the removable cover device of FIG. 1;
FIG. 6 is a top view of the removable cover of FIG. 1; and,
FIG. 7 is a bottom view of the removable cover of FIG. 1.