Lifesource Medium/Standard Size Blood Pressure Cuff UA-280 For Digital LifeSource Blood Pressure Monitors Fits Arm 7.5 to 12.2 inches in circumference 19-31 cm Medium Blood Pressure Cuff from Lifesource is comfortable and easy to use. The arm cuff uses a strong velcro hook and loop fastener that is tested for up to 30,000 uses. Note No Blood Pressure Monitor is Included This is only a cuff. Use the UA-280 cuff on all single tube automatic blood pressure machines manufactured by AND Medical. Note Follow instructions in manual or phone customer service at LifeSource to learn how to modify the exhaust and guarantee accurate measurements. Using the correct size of arm blood pressure cuff is important for an accurate reading. A cuff that is too large will produce a reading that is lower than the correct blood pressure; a cuff that is too small yields a measurement that is higher. With your arm hanging at the side of your body, measure the circumference of your upper arm at the midpoint between the shoulder and elbow. UA-279 Small Adult Arm Cuff Size fits 5.1 7.9 in. 13 20 cm UA-280 Medium Adult Arm Cuff Size fits 7.5 12.2 in. 19 31 cm UA-281 Large Adult Arm Cuff Size fits 11.8 17.7 in. 30 45 cm For use only with digital Lifesource Blood Pressure Monitors. All sales on cuffs are final. No refunds or exchanges. Lifetime Manufacturer's Warranty. This item ships from a separate warehouse and may require extra time for delivery.