Pregnancy bola, pregnancy bola necklace with sound pearl and silver pendant, jewelry gifts, mother-to-be jewelry, mom-to-be gift, mom-to-be gift Pregnancy bola, pregnancy bola necklace with sound pearl and silver pendant, gift jewelry, gift idea, mother-to-be jewelry, mother-to-be gift, mom-to-be gift 🌟 The chain of this necklace and its finishes (rings and clasps) are made of stainless steel which optimizes its strength and its lifespan. The sound of the bola is very delicate and is similar to a slight bell sound. This sound is produced by small metal balls that collide in the bola's internal copper ball when the mother is in motion. From the 4th month of pregnancy, the baby recognizes this harmonious sound that calms and reassures him.