Each bead in these 5cm extensions are 100% certified Natural Baltic Amber that is sourced in Lithuania. Baltic Amber is a traditional European remedy for baby teething, which has been in use for centuries. Each extension is handcrafted and knotted before each bead for maximum safety. It is also easy to fasten, just screw together the ends of the extension with the existing matching screw clasps on your necklace or bracelet.