Underwater Wide Conversion Lens. Official OLYMPUS. This is not a problem underwater. Main Materials/Finishes: Aluminum alloy/Corrosion-resistant hard anodized, Nitrogen gas-filled anti-fog lens. When using the PTWC-01 in combination with the PT-051/PT-050/PT-048/PT-047/PT-045/PT-043 on land, vignetting will occur in the corners of the image.
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