Nikon 40.5mm Drop-in Circular Polarizing Filter for Nikon AF-S NIKKOR 400mm f/2.8E FL ED VR Lens

This Nikon 40.5mm Drop-in Circular Polarizing Filter helps to reduce reflections and glare by filtering out light that has become polarized due to reflection from a non-metallic surface. It is made specifically to fit within the accessory filter slot of the Nikon AF-S NIKKOR 400mm f/2.8E FL ED VR Lens whose front diameter is too large to accommodate a screw-on filter. With that lens, the effect of this filter occurs behind the main glass elements instead of in front of them.