Virtually indestructible design can withstand repeated drops of 5 feet or more. Extra large backlit LCD with 7/8" digits, is easy to read in virtually any light. Splash resistant housing for use in harsh environments. Swivel cuff clip allows the manometer to be re-positioned for easy viewing. Auto off function conserves battery strength. Dual low battery warnings. Recalibration reminder after 10,000 cycles . Systolic assist alerts practitioner to the onset of Korotkoff sounds - makes a great training aid. Deflation rate display promotes proper technique in accordance with AHA guidelines. Pulse rate display at completion of measurement. Manometer works with virtually every cuff on the market. Requires familiar and trusted manual auscultation to obtain blood pressure readings . 2 "AAA" batteries . May be ordered as a complete sphygmomanometer or gauge only for use with existing inflation systems. Lifetime calibration warranty.