I purchased three, put one in my wallet, gave one to a friend and one to my wife. A few days after I gave one to my wife, she went to stay with her parents to help her dad with an outpatient medical appointment while she was waiting for him. She went to get some coffee. She went about 20 feet and notification went off that she wasn’t by her wallet she went back got her wallet so it saved her from leaving it and kept somebody from picking it up. Love it the product.