I have high blood pressure and even though I am on medication the doctor said I should monitor it daily . I got tired of going over to the Walgreen's pharmacy to check it. I saw one and these small things while at a dentist appoitment. I wondered if it worked as well as the bigger ones on the arm so I sat at the pharmacy and checked them both together several times and the wrist cuff came out the same everytime! I now can check it at home and trust the cuff to be right everyime. I do recommend this blood pressure cuff without hesitation. Well done to the seller!