Suggestions for filter replacement: Generally, the filter element can be used for about 3 months. The service life of the filter element can be determined by the color of the filter element (the color of the filter element is darkened due to rust water, foreign matters and other impurities). The replacement cycle may vary depending on the water quality, dosage and water pressure in different places. Feature: 1. Purifies Water: The filter element is made of micron grade PP cotton+calcium sulfite ball, which can effectively remove rust, sediment, particles, residual chlorine, various colors and smells. 2. The faucet filter element is easy to install and is suitable for most faucet filters. Please check the size and type of faucet connection before purchasing to ensure compatibility. 3. The faucet filter element will change color when it needs to be replaced. Please replace it in a timely manner to maintain optimal filtration performance and enjoy fresh water every day. Specification: Filter element material: PP cotton Size: Filter element length: about 25mm/0.98inch Quantity: 5PCS/10PCS/15PCS/20PCS/30PCS/40PCS Package includes: 5PCS/10PCS/15PCS/20PCS/30PCS/40PCS Faucet Filter Note: Due to the different monitor and light effect, the actual color of the item might be slightly different from the color showed on the pictures. Thank you! Please allow 1-2cm measuring deviation due to manual measurement.