ND1.3 Neutral Filter with 5% Transmission Level M28, ND96-1.3
ND=1.3 1.25-inch Neutral Density Filter with 5% Transmission Level M28.5x0.6 thread, ND96-1.3
This is a neutral density (grey) filter that reduces the amount of light and increases the contrast.
It is also recommended for the observation of the Sun. (YOU MUST USE A FRONT SOLAR FILTER AS WELL!)
With the appropriate grey filter you can use the photographic AstroSolar filter for visual observations.
All grey filters can be combined to create the necessary density...