The ornamental design for an implant vial, as shown and described.
FIG. 1 is a perspective view of the implant vial of the present invention.
FIG. 2 is a top plan view thereof;
FIG. 3 is a front elevational view thereof, the rear elevational view, the right side elevational view and the left side elevational view being the same image thereof; and,
FIG. 4 is a bottom plan view thereof.
Phantom lining, where utilized, is for illustrative purposes only and is not intended to limit the claimed design to the features shown in phantom.