As a professional photographer with 30 years of experience, it's my opinion that you'd be hard-pressed to find a better optical-quality variable neutral density filter at this price. This is a great value and given there are two filters, expands the range of creative options even further making this an easy decision.Why would you want a neutral density filter? It allows you to use a wide aperture in bright sunlight to blur the background even on the sunniest day. This is an essential tool for videographers. If you consider the Sunny f/16 Rule where on a clear, sunny day, an aperture of f/16 means your shutter speed is the reciprocal value of your ISO, if your camera is set to 100 ISO, your shutter speed would be 1/100th of a second. The problem is that ISO 100 is almost as low as most cameras go, some professional cameras go down as low as ISO 50, and an aperture of f/16 is simply too much and makes it very difficult to blur the background with nice bokeh. Shooting a lens wide open pushes the shutter speed up far too high for video. Using a variable neutral density filter allows you to darken the ambient light by 1-9 stops with this set of filters, allowing you to use a slower shutter speed AND a larger aperture to control your background blur (bokeh).For fine art photographers, variable neutral density filters allow you to use long, slow shutter speeds in full on sun at smaller apertures and lower ISO settings. That means you can get sharp images from foreground to background with the smaller aperture, and the low ISO gives you the best image quality, and the longer, slow shutter speeds allow you to get soft skies and ethereal water and make people seemingly disappear from busy bridges and scenes because your exposures go from fractions of a second to minutes. A variable neutral density filter is an essential tool in any photographers kit.This set of filters feature Japanese quality optical glass from a Chinese manufacturer and are very high quality. The filter mount is very thin and low-profile glass. You dial in the amount of neutral density by rotating the filter once it's mounted on the lens. The first filter is 1-5 stops of neutral density and is variable for fine-tuning the settings and the second filter is 5-9 stops with infinite variable adjustments.There are markings on the filter from ND2-32, which is 1-5 stops light reduction, and ND32-512 which is 5-9 stops light reduction. These numbers can be confusing because they represent the factor of light reduction as opposed to the f/stop reduction. Between the two filters, you have a range of 1-9 f/stops of light reduction!One of the biggest issues can be vignetting on wide angle lenses and cross-hatching from the polarization of the optics which is how these filters reduce the incoming light. These filters have absolutely no cross-hatching and on my Canon 24-70mm lens (82mm filter size) there was no vignetting at any focal length. This is due to the fact that the filter is slightly oversized, as you can see in the photo and sets away from the edge of the lens. This, however means you won't be able to use a lens hood, which is something to consider when shooting landscapes or video. You'll need to come up with another solution for shielding the lens from direct sunlight while shooting. Easy enough to do with a card or your hand, but definitely something to consider if your exposure is 5 minutes! Your arm might get tired.The filters come with a nice, plastic enclosure that mimic the low profile of the filters and easy to stow in your camera bag. The boxes feature a magnetic flap closure and are nice to keep the filters protected if you have the storage space in your bag. This is a very nice variable, neutral density filter set that I can highly recommend as a must-have addition to your kit. Happy shooting! Get out, explore light, and have fun being creative! I always appreciate thoughtful, honest reviews, and I hope you find my review helpful and insightful.