These mermaid tail necklaces are ideal for kids who use chewing to calm or refocus, by helping to reduce anxiety & stress. With a cool, discreet calming solution when chewing is needed, it can help habits such a fingernail biting, clothes biting or sucking or other sensory habits. Light chewing on these can be a very effective way to help calm, self-regulate, and focus.It's also great for the development of oral motor skills, helps build jaw strength and stability, and exercise the mouth muscles. And, it can help with food texture sensitivity. The mermaid tail is non toxic 100% food grade silicone, BPA, PVC, metal and lead free.Please note that the necklace cord is not designed for chewing. It has a breakfree clasp at the back and a size adjuster on the side.