Product Link:

This filter is optimal for either a OneShotCamera (as in Color Camera), which is either an unmodified Canon DSLR with APS-C sensor, or modified Canon DSLR but with an additional UV/IR Cut Filter. The SVBONY CLS Filter does let UV and IR through!

This filter lets most light frequencies through, which are seen in emission nebulae. With these characteristics, the filter enhances the contrast, which is why it’s called a UHC (ultra high contrast) filter.

M57, the Ring Nebula, 2min single sub as test @ ISO 12800 SVBONY UHC + SVBONY UV/IR Cut by @Astrokonsti
Test Stack of 14 images from the Community Rig by @Zaph, NGC 7023 – “best I could get out of it without darks or proper flats”