HamiltonBuhl Flex-Phones are made from a single piece of EVA foam. EVA is a safe, non-toxic, BPA-free, soft, flexible, nearly indestructible product. Most importantly, the extremely clear sound quality will never exceed 85 decibels, ensuring young developing ears are protected. Flex-Phones are packaged with a snap-on extension band for smaller children - just snap on the extension band for a more snug fit. Flex-Phones headsets feature an in-line microphone, volume control and come with exclusive Dura-Cord - the chew-, kink- and knot-resistant PVC-jacketed, braided cord.