I like having these on hand after drinking because it’s nice to know if it’s safe or not to breastfeed. I’ve tested multiple times (no drinking, light drinking and heavier drinking) and the test strips indicate how much is in my system still. However, I have now opened two packets that are entirely empty. Kind of annoying given the price. Still giving 4 stars since they work but they need to figure out packaging so there’s not empty packets in the box.