What are the functions of a filter with mount?
The mount (usually a metal or plastic bezel) provides a stable support structure that facilitates the integration of the filter into the optics (e.g., filter wheels, lens cartridges, microscope modules, etc.) and avoids direct contact with optical surfaces.

What are the advantages of a filter with mount?
Prevents chipping of filter edges (especially brittle materials such as infrared crystals or narrow bandpass filters).
Standardized sizes (e.g., Φ25mm, Φ50mm) are easily compatible with commercial optical mounts.

Filters with mount are indispensable components in complex optical systems, not only to provide mechanical stability, but also to optimize the optical path performance (to reduce stray light, to ensure perpendicular incidence). When selecting a filter, it is important to weigh the bezel material, thickness and functional design according to the application scenario (e.g. laboratory, industrial, outdoor).