The ornamental design for a connectiondevice, as shown and described.
FIG. 1 is a first perspective view of the connection device;
FIG. 2 is a second perspective view thereof;
FIG. 3 is a third perspective view thereof;
FIG. 4 is a rear elevational view thereof;
FIG. 5 is a left side elevational view thereof;
FIG. 6 is a front elevational view thereof;
FIG. 7 is a right side elevational view thereof;
FIG. 8 is a bottom plan view thereof; and,
FIG. 9 is a top plan view thereof.
The heavy dot-dashed lines are for illustration of the boundary between claimed subject matter and unclaimed subject matter only and form no part of the claimed design. The thin dashed lines are for illustration of environmental subject matter only and form no part of the claimed design.