The ornamental design for a monitoringdevice, as shown and described.
FIG. 1 is a perspective view of a monitoring device showing a fifth embodiment of my new design.
FIG. 2 is a top view of the monitoring device of FIG. 1.
FIG. 3 is a bottom view of the monitoring device of FIG. 1.
FIG. 4 is a first side view of the monitoring device of FIG. 1.
FIG. 5 is a second side view of the monitoring device of FIG. 1.
FIG. 6 is a front view of the monitoring device of FIG. 1; and,
FIG. 7 is a rear view of the monitoring device of FIG. 1.
The broken line showing of a monitoring device is included for the purpose of illustrating environmental subject matter and forms no part of the claimed design.