Eremana Eremana Necklace Black Free Size Size: ・Length (inner circumference) 48.5cm ・Thickness 5.5mm Material: ・Body: Silicone, Sumi (charcoal) powder Black Eye: Copper wire, Ceramic charcoal, Styrene thermoplastic elastomer This is an electromagnetic wave protection necklace developed by Dr. Nobuhiro Maruyama. I have one myself and it was good, so I bought it for my family, but they didn't use it and it's been stored away. For anyone who needs it. Thank you for looking.