I've owned this filter for a few years and it's ideal for capturing photos will long shutter speeds, blurring movement. I've used the lens a few times for water photos, but don't use it often enough to keep it. The filter is for a 67mm lens and it's in good condition, with no major scratches or marks.
Hoya Description
The ND64 is a dark neutral density filter with a filter factor of 64, meaning there is 6-stop light loss. This is a great filter for slowing down shutter speeds to capture motion. An example: In daylight, maybe the slowest shutter speed possible without a filter could be 1/60 sec at F/22 By adding the HOYA PRO1 ND64, a shutter speed of 1 full second would be possible. Another use of the ND64 would be controlling depth of field. With these strong ND filters, a much wider aperture can be used. Wide apertures like F/1.4 and F1.8 create a very shallow depth of field and have the effect of isolating the subject from the background. Creative possibilities are endless with this type of filter.