This small blood pressure cuff fits upper arms 6.3” to 9.4” (16 – 23.8cm) and is ONLY guaranteed compatible with LifeSource brand blood pressure models UA-767PSAC and UA-787EJ. The tapered fit is designed to snugly and comfortably fit around your arm. All LifeSource blood pressure cuffs are durable and come with a 2 year warranty. IMPORTANT: Measure your arm before you purchase your cuff. Many people might think it’s as simple as using the same size as your t-shirt, but that’s not the case! If your cuff is too small, your blood pressure reading will be artificially high. If your cuff is too large, you may get a reading that is lower than your actual blood pressure. 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. NEED HELP? Our dedicated customer service team can be reached at (888)726-9966, and they can answer any questions or concerns you might have regarding your device. ABOUT LIFESOURCE: LifeSource by A&D Medical is a doctor recommended brand of health monitoring devices designed to help patients and their families track and troubleshoot with their doctors, all from the comfort of their homes. The technology in the blood pressure monitors, activity monitors, scales, thermometers, and smart devices help make keeping track of your health easy.