Filters can be of various types and used for different purposes.
There are different types and they are divided into low-pass, high-pass or band-pass, depending on the wavelengths you want to attenuate or transmit.
It is also possible to process and combine, with bonding, different thicknesses of various types of optical filters belonging to the UG, BG, VG, GG, OG, RG, etc. classes.