The L-Ultimate is a 3nm dual band filter designed to drastically reduce the effect of light pollution. The 3nm isolates the nebulae's emissions into H-Alpha (red) and OIII (green-blue). It blocks light pollution, maximizes the signal from nebulae, and darkens the sky background. It also blocks artificial light from mercury vapor lamps, high and low pressure sodium vapor lights, and unwanted natural light caused by the emission of neutral oxygen in our atmosphere, maximizing the transmission of the main emission lines of the nebula in OIII (496nm and 500nm) and H-alpha (656nm). Used with DSLR, color/MONO CMOS and CCD, this filter is suitable for telescopes with an f-ratio of f/4 or higher (slower).
Didn't imagine it would be so big. This is some serious machine-worked piece and easy to adapt to any tripod with multiple configuration options. The price was a bit high but the product is well worth it as you will only buy on in your life time.