Pro pohodlnější pozorování na Měsíci. Průměr objímky: 2″ Universally usable variable polarizing filter with a 2″" filter thread. This variable polarizing filter allows for a continuous adjustment of the image brightness. This is very helpful to level strong differences in contrast of different observation objects individually. Particularly for lunar and planetary observations but also for solar observations this filter prevents an outshining of details.