Includes: 3 Mesa replacement filters that fits and is compatible with the Simple Modern Mesa Straw LidsActivate: Before using a new filter, submerge in water for 30 seconds to activate the filter. Gently rinse in all directions to remove loose carbon particles. Seeing a small amount of carbon particles is normal.Assemble: Insert filter into straw piece and press until flush with top of straw. Align the lid and straw and twist into lid to lock.Duration: One carbon filter lasts 40 gallons - approximately 2 months.