This wide angle conversion lens can be mounted directly on to your Olympus underwater housing with M52 threaded mount. It gives you a wider view angle (95°) under water. it has a compact size and therefore handy to use and to exchange. With the optional Dome Lens Unit IIIA you get a view under water of approx. 141°.

When you use this lens on land, it gives you an extra wide-angle of 159° (!) to make fisheye images without complicated and expensive gears.

Newly designed optics provides quality underwater images
Totally renewed optical design effectively suppresses flare/ghost even in backlit condition to provide sharp and high quality image together with optimal lens positioning relative to camera master lens.

Minimum Focusing Distance 0 cm
A subject just in front of the lens or distant seascape never get out of focus. The lens won’t limit shooting distance.
 
Usable with All Zoom Range
Unlike conventional wide conversion lenses, which are recommended to be used only at zoom wide end as zooming results in poor image quality in peripheral areas, this lens manages to keep high quality image regardless of camera's zoom setting.
 
Optical Anti-Reflection Coating (AR-Coating)
All component lenses are finished with optical anti-reflective coating, which thoroughly suppresses flare and ghosting providing stable image quality in backlit scenes where flare and ghosting are likely to occur.
 
Interchangeable Lens Mount
Replacing the original lens mount with an optional lens mount can convert lens type. 

Specifications INON UWL-95S M52:

Diameter 90 mm/3.5 in
Length: 48.3 mm/1.9 in
Weight: approx. 392 g (13.8 oz) on land and 611 g (21.5 oz) under water
Mount: INON M52 Mount
Depth rating: 60 m/196.9 ft
Body material / finishing: Corrosion-resistant aluminum alloy /rigit black almite
Glass / coating: Optical glass / both side anti-reflection coating
Construction / magnification: 3 groups 4 elements /0.63 (afocal system)
Max. view angle: Underwater: 95.1° / Air: 159.0° (actual depends on camera &  housing used)