Lumicon 2 inch Deep Sky Filter. Will screw onto 2 inch thread eyepiece, T-ring adapter etc.
Comes with holder.
Immaculate condition.
Here is a write-up.....
http://www.myastroshop.com.au/produc...um-filters.pdf
There are currently on special for US$199.95 direct from Lumicon
$200 shipped anywhere in Australia