Really really disappointed with these and the customer service. I tested exactly like the instructions prompted me to and kept getting negatives. I tested on the exact days I was supposed to because I was taking ovulation tests to make sure I was having a LH surge. I was so disappointed and thinking I hadn’t ovulated because of these tests. I entered them into the app and would even delete the app and re download them to put the results back in to see what they’d be and they would give me a different reading Everytime so I emailed support about it and never even got a response! Oh and guess what ……… IM PREGNANT….. so the tests were most certainly wrong. I wish I hadn’t of wasted my money.