Nikon Volpi Green Fiber Optic Illuminator Filter. The filter fits into the provided slot of some earlier Nikon lamp supply units and also into the Volpi Inaterlux 4000-1, 5000-1 and 6000-1 lamp supply units. The filter is the standard GIF with dimensions of 5.74 mm thick, 26.25 mm wide and 50.41 mm length for insertion depth. This item is new still in original packing. Thanks for looking!