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Alex,
The second filter says it is for Hb + O-III observing, which defines a UHC or narrowband filter. It does that, but with a little too much extra thrown in. It looks as broad as the Baader UHC-S.
Jason,
The NPB also has a transmission in the deep red. In really large scopes (say 400mm+), that translates to a better view of reds in nebulae. Some people like it, some don't. The Orion Ultrablock has literally no deep red transmission, so you won't see any reds at all. Fortunately, all nebulae transmitting H-alpha at 686nm also transmit H-beta at 486nm, and there our eyes are very sensitive.
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