These are a must have for breastfeeding moms who like to enjoy having drinks from time to time without having to guess if the alcohol is still present in their breastmilk. You MUST follow the instructions accordingly for them to work. I put a timer on my phone to make sure I read the results exactly at 2 minutes. If you wait longer than that, you will see a positive result even if it's negative which has happened to me before with these strips. The picture here is right after 3 margaritas with the results showing right after the 2 minutes. I tested again when I figured it was out of my system, and that strip remained its cream color so I knew I was good to feed my baby. A must have for breastfeeding moms!