High-precision, blood pressure3mmHg, pulse5%. 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 ArmsDesigned 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).