Specifically designed for the Phantom 4 Pro Obsidian, ND filters reduce the amount of light that reaches the sensor. The filter gives you more control over your recordings by allowing greater control over aperture, exposure, and sensor sensitivity settings. In simpler terms, the ND filter helps you avoid overexposed images. The ND4 filter allows 1/4 of the incoming light to pass through, equivalent to a 2-stop filter. The ND8 filter allows only 1/8 of the incoming light to pass through, equivalent to a 3-stop filter. The ND16 filter allows only 1/16 of the incoming light to pass through, equivalent to a 4-stop filter. It reduces the captured light by 3 stops to effectively prevent overexposure.