The ornamental design for an elastomericfastener, substantially as shown and described.
FIG. 1 is a front view of an elastomeric fastener comprising a new, original and ornamental design;
FIG. 2 is a right-hand side view of an elastomeric fastener comprising the new, original and ornamental design, the left-hand side view being a mirror image thereof;
FIG. 3 is a top view of an elastomeric fastener comprising the new, original and ornamental design;
FIG. 4 is a bottom view of an elastomeric fastener comprising the new, original and ornamental design; and,
FIG. 5 is a front, top, left-hand side perspective view of an elastomeric fastener comprising the new, original and ornamental design, the portions shown in broken lines forming no part of the design.