Our raw lemon amber necklaces have the highest content of succinic acid for the highest pain relief. They are certified Baltic amber and come with their individual certification of authenticity. All of our necklaces are approximately 12" in length and have a screw clasp for greater durability. The necklaces are double knotted between each bead and are made with a silk thread so that they will break under 15lbs of pressure.Tiny Footprints, Inc.