This necklace is made with beads of genuine Baltic Amber from Lithuania. Amber is a tree resin that has been fossilized for millions of years. When worn against the skin, the skins warmth releases healing oils from the amber, providing anti-inflammatory and analgesic effects. Historically, Baltic Amber has been used as a traditional remedy for many ailments. Choose the best size for your baby. Not too loose, not too tight. Just right size will NOT come up over the chin. Not meant for chewing. Breakaway clasp. Small = 11" to 11.5" (28cm) Medium = 12" to 12.5" (32cm)