High-precision, blood pressure±3mmHg, pulse±5%. A color scale indicator on the screen for WHO guidelines easily interprets whether the blood pressure is high or low. ✔️【Adjustable D-ring Arm Cuff Fits Most Arms】Designed with soft nylon material and adjustable velcro, the blood pressure cuff can be adapted to different upper arm circumferences from 8.7" to 15.7" (22 - 40cm).