The Katana has a lens interchange system that is easy to use and incredibly quick. If the clouds suddenly decide to ruin a bluebird day, you can be ready with the perfect lens in just a few seconds.
You just need to open the lever on the left side of the goggle, lift the lens on the side of the lever to free it, and there you go: you're done.
The Katana is available with two Zeiss lenses, one for sunny days and one for bad weather conditions.
In alternative, you can choose to have it with the awesome The One photochromic and polarized lenses that are designed to work well in all conditions.
The Katana's frame doesn't protrude from the sides of the lens, improving the field of view on the vertical axis; therefore, providing a better vision at the top and at the bottom of the lens. On the sides the frame hosts the quick lens interchange mechanism.