"Phien Rakuwa Necklace Wire Extreme with premium design and ultra-light material brings a wonderful experience! Improve blood flow and enhance performance. Loved by athletes who spend all day training. Waterproof and sweatproof. Technology: Patented Metax technology. Suggested Use - Helps relieve ongoing stress. - Helps improve blood circulation. - Enhance muscle strength and flexibility. - Helps relieve pain or soreness. - Great for sports or daily activities. Material : Body (stainless steel, nylon), Buckle (aluminum, urethane). Size: 40cm and 50cm.