The removable SportDiver Red Filter for Blue Water from SeaLife restores natural underwater colors. The red color filter is designed for blue water conditions. It is most effective at depths of 10-60', when not using an external light. The filter also serves as a protective cover for the SportDiver's optical glass port. Compatible with the SeaLife SportDiver underwater smartphone housing, the filter easily attaches/removes to the SportDiver optical lens frame while underwater. It is made of optical acrylic infused with proprietary color pigments and comes with a lanyard for attaching the filter to the housing.