This is a very easy and nifty way to keep the interior of your refrigerator healthy. ( It's similar to buying a large pack of furnace filters, and then having them on hand. ) A small box of 6 of these filters arrives promptly. Each one is separately wrapped. It is super easy to install. And additionally, there is a space for you to record the date on the filter, so that you can see when you installed the last one. The date remains visible in the filter compartment In your fridge. Keep the box handy, under the kitchen sink, or in the laundry room, and change the filter every three to six months.