Haida Circular Polarizing (CPL) Filter is made of Optical
Glass.
Haida CPL Optical Glass filter can remove unwanted reflections from
non-metallic surfaces, such as water or glass, and saturate colors
providing better contrast. The filter factor varies according to
how the filter is rotated and its orientation to the sun.
Designed for Auto-focus SLR camera, also, can work on manual
system.