High polished 14mm brass ball caged in sterling silver drop-shaped filigree which chimes when shaken. Pregnant women often wear these pendants low on the belly.hen the Harmony Balls emit their sweet sound, babies can hear and respond to it as early as the 16th week of pregnancy. Once these babies are born, mothers hang the harmony balls on a shorter necklace. Its sound will soothe the upset baby and remind him/her of the time in the mother's womb.