The Aquasana AQ-4125 Shower Water Filter is a screw-in filter designed for showers, featuring a universal connection thread for easy installation. Made of bacteria-resistant plastic material, this shower head filter is suitable for use in the bathroom. With a matte finish and a weight of 2 lbs, it is compatible with Aquasana AQ 4125 and AQ-4100 models, providing clean and filtered water for your showering needs.