The Lee 3x3" UV-2B Polyester Filter is a haze UV filter that protects your lens from dust, moisture, and scratches that can lead to costly repairs.
Haze filters provide correction for Ultraviolet (UV) light that can register on film and videotape as a bluish cast and can obscure distant details. Ultraviolet filters allow you to correct for the UV effect to varying degrees. If desired, they can be left on the lens at all times for protection.
The UV (2B) filter is useful for high altitude photography and eliminates almost all the present UV light.