Correct measurement attitude: Take a deep breath before measuring your blood pressure and then relax your body. Please extend your arm a little towards the table, holding the palm of your hand and the loose fingers. Place a towel between the elbow and the blood pressure monitor to keep the upper arm stable. Maintain your correct posture Keep the blood pressure monitor aligned with your heart. Technical specifications: Display mode: liquid crystal display Measurement mode: oscillometric pressure relief method Power supply: two AAA (3V) alkaline batteries (not included) Measuring range: (20-280) mmHg / (2.7-37) kPa (blood pressure) (40-160) Time / min (pulse frequency) Storage temperature: -20 ° C ~ 50 ° C Storage humidity: 15% to 90%. Operating temperature: 10 ° C ~ 40 ° C Operating humidity: 40% ~ 85% Pulse: (40 ~ 200) times / min Resolution: 1mmHg (0.1kPa) Accuracy: ± 3mmHg (± 0.4kPa) Note: Read the operating instructions carefully before using the sphygmomanometer to enjoy a better experience. Before measuring blood pressure, sports, smoking or taking stimulants, sedatives such as coffee or alcohol are not allowed. Place the sphygmomanometer with the position of the heart at the same height. Blood pressure should be measured two or three times in a row, every three minutes, then you can use the lowest one as a result. Package contents: 1 x wrist blood pressure monitor 1 x user manual