The UCL-165M67 is high magnification close-up lens providing 165mm focal length (+6 diopter).
Adding it to the front of your housing's flat port will reduce your lens' minimum focus distance, allowing you to get closer to a subject and enabling high magnification close-up photography.
This lens works both above and below water and is usable through the entire zoom range (vignetting may be present at wide angle focal lengths). It can be used with both compact cameras and interchangeable lenses for DSLR or mirrorless cameras. It is compatible with any port that features a 67mm thread on the front.
The lens construction is 2 elements in 2 groups with high quality optical glass. The glass lens element features an inner coating to suppress optical aberrations more effectively and enhance optimal performance.
The lens body has a male 67mm thread on the housing side for nearly universal compatibility, as well as a female 67mm thread on the front side allowing you to stack lenses for double magnification.