The ornamental design for a powerextensiondevice, as shown and described.
FIG. 1 is a perspective view of a first embodiment of an ornamental design of a power extension device.
FIG. 2 is a right side view of the first embodiment of an ornamental design of a power extension device.
FIG. 3 is a left side view of the first embodiment of an ornamental design of a power extension device.
FIG. 4 is a front view of the first embodiment of an ornamental design of a power extension device.
FIG. 5 is a back view of the first embodiment of an ornamental design of a power extension device.
FIG. 6 is a top view of the first embodiment of an ornamental design of a power extension device.
FIG. 7 is a bottom view of the first embodiment of an ornamental design of a power extension device.
FIG. 8 is a perspective view of a second embodiment, substantially identical to FIGS. 1 through 7 of the first embodiment but showing a different base, of an ornamental design of a power extension device; and,
FIG. 9 is a perspective view of a third embodiment, substantially identical to FIGS. 1 through 7 of the first embodiment but showing a clip facing the back, of an ornamental design of a power extension device.