Comes in two sizes: small (11.5?/28 cm) or medium (12.5?/32 cm): Sizing considerations: It should not be so loose that the child can lift it up into his/her mouth, but it should not be so tight that it will be uncomfortable. You should try the necklace on the baby to gauge the proper fit or measure using a piece of yarn. A genuine Baltic Amber teething necklace is a natural form of pain relief for teething babies. Amber itself is a fossilized tree resin and contains “succinic acid” which, by body warmth, is released into the skin when worn. Succinic acid provides anti-inflammatory and analgesic properties. For teething baby, this means pain relief and reduction of the inflammation of the gums that accompanies teething.