How to Prime a Fluoride Filter Using the Prime Button Prime the fluoride filter using the thick tan gasket (called the prime button). One prime button is included with each fluoride filter purchased. 1. With the blue caps in place, clean the outside of each fluoride filter cartridge with water and mild dish soap, then rinse well. 2. Using clean hands, remove the two blue caps from each end of both cartridges. 3. Place the rubber prime button (tan) over one end of the fluoride filter and align the holes in the filter with the holes in the rubber gasket. 4. Press the prime button up onto the sink faucet so that the prime button forms a seal between the faucet and the fluoride filter. Place your thumb on the top of the faucet to apply pressure to create a better seal (as shown). 5. Pressing the prime button against the faucet, slowly turn on the cold water and allow the water to fill the cavity of the filter and flow out the other end. 6. Allow the water to flow for at least 1-20 minutes until the water runs clear. 7. Turn the fluoride filter over and prime the other end (reverse the water flow), repeat steps 3-5 until the water is clear in both directions. 8. To determine if the filter is fully primed, collect the filtered water into a clear glass and hold it up to the light to see if the turbidity in the water has disappeared. If not, continue to prime until the water is clear. 9. This filter is now primed and can be installed. 10. Repeat priming steps 1-7 for each additional fluoride filter. Note: Different factory batches may have different appearance labels, which will not affect the use of the product Material: Activated Carbon Color: As shown in the picture Package Contents: 2 x Water Filters Above packaging content only, other products are not included. Note: Light reflection and different monitors may cause the color of the item in the picture to be slightly different from the actual product. The measurement allowable error is +/- 1-3cm. Note: Due to the light and screen setting difference, the item's color may be slightly different from the pictures. Please allow slight dimension difference due to different manual measurement.