The Olympus PTWC-01 is a high quality 100° wide angle conversion lens that works on many of the Olympus housings with ports that have a 67mm thread. The lens has a magnification of 0.6x. The large size of the lens blocks the camera's built-in flash so an external flash must be used.
The lens allows you to get closer to large subjects. This will improve your underwater photos by increasing contrast and color saturation.