Easy to Install: This shower filter replacement cartridge is simple to install. Unscrew the shower filter outer casing, insert the replacement cartridge, and screw the outer casing back on. No tools required. Please pay attention to the installation direction. It works with both hot and cold water. 4Pcs Set: The package includes 4 shower filter replacement cartridges. They remove chlorine, reduce heavy metals, fluoride, and odors. They soften water and minimize water stains, promoting healthier skin and hair, and are especially suitable for sensitive skin. Gentle Cleansing: The cartridges feature multi-stage filtration that softens water and reduces harmful chlorine, dirt, and heavy metals. This supports healthier skin and hair and provides a gentle cleansing experience with a relaxing spa feel at home. 20 Stage Design: Each replacement cartridge uses a 20-stage design to greatly reduce chlorine, dirt, and unpleasant odors. It also helps reduce limescale, which can cause dry skin, itching, eczema, pustules, acne, brittle nails, and more. Use scenarios: - Daily showering to improve skin and hair health, especially for sensitive skin. - In areas with hard water to reduce mineral buildup and water stains. - After exposure to chlorinated pools or city water to remove residual chlorine and odors.