Best used in tandem with a base filter that blocks the IR spectrum.
The IDAS Nebula Booster 3 (NB3) Series filters pass the OIII and SII wavelengths unlike the Nebula Booster 2 series that swaps SII for Ha. Both the 2 and 3 series are dual-band filters while the Nebula Booster 1 series are tri-band. The 2 and 3 series filters are best paired with any other base filter that is used to block the IR spectrum, as these do not. Most commonly the paired base filter is the IDAS NGS 1, which is shown in the chart below.