[Filter Sticks Size]0.31(Diameter) x 2.75 (Length)inch. You can cut it to fit with your diffuser/humidifier if necessary. [Replacement]We advise our customer to replace the filter after 3-4 months use (depending on usage and water quality). [How to Use]To see a better performance, we advise user to soak a filter stick to be wet completely before inserting to the humidifier. [Advantages]Prolong the service life of diffuser: if the diffuser/humidifier is always complete-blocked or half-blocked, it become hot and become broken easily, we highly recommend you to use water-solubility essential oil and clearwater. Usually 1 to 2 weeks, replace the filter, or easy to connect the machine. If you regularly use essential oils, need to replace 3 - 6 days. Size:7cm in length and 0.8cm in diameter Material:Cotton swab Colour:white Package Contents: 150 x Humidifier Sticks Cotton Filter Sticks(Excluding other display items) Only the above package content, other products are not included. Note: Light reflection and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.