Product information: Material: Aviation grade titanium alloy Specification: 7.9 * 2.8mm Weight: about 4.5g Battery life: 5-7 days Available colors: silver/black/gold/Rose Gold Optional size: 6#7# 8# 9# 10# 11# 12# 13# Waterproof grade: IP68 Certificate: CE/FCC/battery report/ROHS/RED Applicable people: fashionable people who pursue new technology products; People who pay attention to health management; Regular exercise