Features Large LCD display:33.8mm*29mm Unit conversion:mmHg,kPa/mmg; 2 users,99 memories per user IHB,Irregular heart beating sign WHO,indicating blood pressure level in 4 colors Average of latest 3 records Low power detection Over pressure protection,295mmHg(20ms) Automatic Switch-off: Error message indication:Date&Time indication Voice(option):AC adaptor(option) Power Requirements 2pcs*”AAA”batteries