Product details of Electronic & Digital Blood Pressure Monitor with Voice Function Large LCD size : 80 x 72mm; LCD and START/STOP button backlight 2×90 groups memory function; Average calculating for the latest 3 times measurement value; Blood pressure classification (WHO) indicator; Irregular heartbeat (IHB) indicator; Year/month/date/time function; Accuracy :Pressure /-3mmHg; Pulse /-5%; Power by DC 6V(1.5V 4Pcs AAA size batteries) Not incluted Automatic power-off function.