This ingenuous little gadget was developed by a lady who kept forgetting whether she took her pills and did not want to organize them in a larger pill holder. So, she designed this small, slightly curved stick on device with 4 separate moving indicator knobs. You use the adhesive backing to stick the unit on your bottle. If you take 4 pills from one bottle each day, every time you take a pill you push the indicator to the left. At the end of the day, when you have taken all 4 pills, you simply push the indicators back to the right and start the regimen the following day. We include 4 units since many people take pills from more than one bottle.