Watch Strap Adapter

FIG. 1 is a front perspective view of a watch strap adapter, showing my new design; FIG. 2 is a rear perspective view thereof; FIG. 3 is a front elevation view thereof; FIG. 4 is a rear elevation view thereof; FIG. 5 is a left side elevation view thereof; FIG. 6 is a right side elevation view thereof; FIG. 7 is a top plan view thereof; FIG. 8 is a bottom plan view thereof; and, FIG. 9 is a perspective view thereof showing a configuration of use. The broken lines in the drawings show portions of the watch strap adapter that form no part of the claimed design. The broken lines in FIG. 9 illustrating a watch strap depicts environmental subject matter that forms no part of the claimed design.