I bought this filter a couple of years ago but have used it only once. I found this description of it on the net:-
"The 2" Sirius Optics NEB1 light pollution reduction (LPR) or “nebula" filter has a bandwidth that splits the difference in width between a narrowband high contrast Oxygen III line filter and a conventional wideband filter. Like any good light pollution filter, the NEB1 effectively blocks the effects of city light pollution. Emission nebulas stand out more clearly against a darker sky background, although stellar objects lose some intensity. Sirius Optics considers that this compromise will satisfy the needs of the majority of users. When compared with the more heavily blocked image through a narrowband filter in moderate light pollution locations, however, the wider bandwidth of the NEB1 increases the amount of glowing nebula detail visible."
Comes in original case with spec sheet. $80 plus postage.
Cheers.
