The WonderPana FreeArc provides the freedom to use and rotate 6.6" and 145mm filters on your Wide and Ultra-Wide Angle Lenses. Because of the construction of these lenses, it's normally impossible to install filters as there are no filter threads. Additionally, standard filter sizes are not large enough to adequately cover the lens's wide angle view. The WonderPana FreeArc changes all that by providing a complete kit for mounting our collection of both round and square filters. The all-metal Core attaches directly onto the lens with a secure mounting system. With The Core in place, you can now mount any of Fotodiox's 145mm round filters.PLEASE NOTE:The WonderPana Freearc you see on this page is custom engineered to fit theNikon 14-24mm AF-S Zoom Nikkor f/2.8G ED AF Lens. It will not fit other lenses, so it's important that you chose the correct Wonderpana Core system for your particular lens model. You will have to remove your lens from the camera in order to mount the filter holder.REMOVE the protective sheet from the 6.6x8.5” rectangle filters before use. They may appear scratched and blemished be aware that this is simply the protective tape.For even more filter flexibility, mount the 6.6" Filter Brackets (these mount without tools on either side of The Core). Once attached, you can easily slide in our 6.6” square filters, which are among the largest and most durable in the business. With the FreeArc, the filter stage is rotatable 360 degrees. The Wonderpana FreeArc can accommodate either two square filters, or one round and one square simultaneously.Kit Includes:WonderPana FreeArc Core for Nikon 14-24mm AF-S Zoom Nikkor f/2.8G ED AF LensWonderPana 145 Heavy Duty Inner-Pinch CapWonderPana 6.6" Wide Filter Holder BracketWonderPana 145mm Slim Circular Polarizer FilterWonderPana 6.6x8.5" Graduated Neutral Density 0.6 (Grad-ND4, 2-Stop) Soft Edge FilterAll pictures are for illustration purposes only. Actual product may vary slightly due to ongoing improvements in design.