Dear customer, Thank you for choosing our products. If there is any problem with our products, please contact us through the order information. We will be happy to serve you and solve it for you as soon as possible within 12 hours, thank you Cotton Material --- The humidifier filter sticks is made of filter cotton material , porosity distribution,absorbent particularly strong, water storage capacity, volatile stability,help your humidifier work better. Replace Time --- When you find the diffuser/humidifier produce less steam or even stop work, and the machine become more and more hot ,try to replace the filter and no worry about the service life about the humidifier. Usually 1 to 2 weeks. High Effectively --- Not water-soluble, non-stick blocking foam filter will enable a pure stream of water steam to freshen the air, which will ensure your ability to breathe more comfortably. Easy to Use --- The humidifier wicks are simple to remove and install, allow you to finish installation in few seconds, please soak a filter stick to be wet completely before inserting to the humidifier; It is recommended to use tap water and don't drip in essential oils to be soaked. Kindly Suggestion --- To see a better performance, we advise user to soak a filter stick to be wet completely before inserting to the humidifier and turning it on. The filter cotton sticks compatible for USB water bottle caps humidifier, can be sheared in shorter for your own diffuser with the same size.