The ornamental design for an ear-mountable bio-sensor device, as shown and described.
FIG. 1 is a rear perspective view of the ear-mountable bio-sensor device showing our new design;
FIG. 2 is a front perspective view thereof;
FIG. 3 is a side view thereof;
FIG. 4 is another side view thereof,
FIG. 5 is a rear view thereof;
FIG. 6 is a front view thereof;
FIG. 7 is a top view thereof; and,
FIG. 8 is a bottom view thereof.
The broken lines immediately adjacent the shaded areas represent the bounds of the claim, while all other broken lines are directed to environment and are for illustrative purposes only; the broken lines form no part of the claimed design.