The “Huit Blanc” version of the “Royal Pop,” a pocket watch that is the result of a collaboration between Audemars Piguet and Swatch. The collaboration hit stores Saturday and caused a frenzy in some locations. (Photo courtesy of Swatch Group)

The back of each Royal Pop watch is Andy Warhol-esque and allows the wearer to see the watch’s movement, a new manual-wind version of the Swatch Sistem 51.