Injector Pen

FIG. 1 is a front bottom perspective view of an injector pen showing my new design; FIG. 2 is a front top perspective view thereof; FIG. 3 is a front view thereof; FIG. 4 is a rear view thereof; FIG. 5 is a bottom view thereof; FIG. 6 is a top view thereof; FIG. 7 is a left side view thereof; and, FIG. 8 is a right side view thereof. The unshaded rectangular region within the shaded area forms no part of the claimed design. The broken lines depicting the remainder of the injector pen form no part of the claimed design.