try Optolong (via Cyclops Optics)...
https://www.cyclopsoptics.com/hrpiw-...-lrgb-filters/
http://www.optolong.com/en/products/...to-filter-lrgb
I recently bought L-Pro from them, it is very good and passband is as per add (tested by myself).
Price was significantly lower than Astronomik and/or Baaader equivalent (they both claim this filter is "cheap" and "bad copy"... but I found it to be low cost and actually very good performer.