At the beginning of the month, distribute your pills into the container marked with the day of the month, up to 31 days. Each compartment holds up to 24 aspirins. An extra compartment can be used for "as needed" medication. Durable clear plastic enables you to see whether or not you took your medication. If you don't have enough for the month, you will know to have your prescription renewed before you run out. Measures 11" x 3.25".