This filter is not an astronomical filter in the classic sense! Rather, it is designed to enable converted DSLR CCD and CMOS cameras, in which the built-in IR filter has been removed or replaced by a modified IR filter, to be used again for terrestrial photography.
The OWB (Original White Balance) filter shifts the entire spectral range of the converted DSLR camera so that it can be used again for terrestrial photography without restriction. This eliminates the decision to use a camera exclusively for astrophotography, which can be quite expensive!
How it works: The OWB filter has been so carefully calculated and designed that the images from the converted DSLR camera once again deliver results that correspond to the human eye's perception of daylight. This enables the camera to work with the sizes it is familiar with for the various preset white balance values and, of course, with automatic white balance (AWB). This was not possible with converted DSLR cameras without a filter.
