Panasonic blood pressure monitors has a digital filter sensor that detects and isolates only the essential pulse oscillation, and eliminates other noise functions for a proven accurate measurement. The ew-bu04w allows for one-touch auto inflate which allows for readings to be taken during inflation to prevent over-tightening of the cuff. Other main features that this unit has is a irregular pulse function/body movement detection, that insures maximum accuracy and will automatically detect any arm movement or irregular pulse and will display a icon alerting you to retake the measurement. Hypertension readings are very important and this unit will alert you to those readings by displaying a flashing number. The cuff circumference is approximately 7 3/4 inches to 15 inches. The slim design makes it convenient for storage or portability with the cuff rolling around the monitor and fitting neatly into the included storage pouch. This unit as comes equipped with aaa batteries. Optional large cuff (ew3901s) is available and well as a AC adapter (ew-2b02w). dimensions are: 1 3/4 inches(h) x 6 12/ inches (w) x 2 3/4 inches (d), 7.4 ounce (without batteries).