Probe frequency: 1MHz±15% Measure time: Single < 25s, Repetition <75s Measurement theory: Critical Angle Side Wave Theory Ultrasound Parameter: SOS. T-score Other parameters: Z-score, Z value, T value, Bone physiological age. BQI. RRF. EOA Operation system: Windows XP or above Suitable population: Baby, Children, Adult (including pregnant women and the elderly)