The 4 x 4" PROSTOP Neutral Density 3.0 Filter from Hitech is used when you need something to reduce your exposure by 10 stops. This unique and powerful filter will now permit you to easily "blur" images such as moving water, cars, sports and other subjects. The effect of this filter permits you to use much slower shutter speeds as well as wider lens apertures.
You can even combine this filter with other filters such as graduated neutral density filters to achieve additional special effects. The 4 x 4" format gives you the freedom to use the PROSTOP with many different lenses and is made to exacting standards. It is best used for outdoor, nature and location photography. The PROSTOP is designed with a special rubber gasket surrounding the filter to help prevent any ambient light from intruding into the image.