found at DigiDirect
The HOYA 52mm ND Variable Density II Filter minimizes the vignette effect often experienced when shooting with wide-angle lenses. In this updated version, Hoya improved the frame of the predecessor Variable Density filter, making it thinner for better handling of vignetting. The filter features a dedicated knob for precision rotation between an adjustable neutral density range of ND3 to ND400 (1.5 to 9 stops). It also allows you to attach an optional lens cap. It supports lens caps that are one size larger than the filter size.
Note: Product is shown in use for illustration Only, additional equipment is not included.