Twin filter kit containing a Hoya Multi-Coated UV and a Hoya Slim Circular Polarising filter. Ultra-Violet (UV) rays, although invisible to the human eye, can cause a hazy, bluish cast in photography. The Multi-Coated Hoya UV filter effectively eliminates UV light of wavelengths shorter than 370nm to give clearer images with more neutral colour balance. No exposure compensation is necessary. Use of this filter is recommended in most situations as a full-time lens protector, but especially when photographing scenes such as mountains, beaches, areas of snow, and any other situations where there is a large amount of UV light present. Using the Circular Polarising filter, reflections and glare from non-metallic surfaces (such as water and glass) can be reduced significantly. It also helps to greatly reduce the haziness which can be caused by atmospherics and will improve colour saturation, as well as providing dramatic contrast between subjects such as blue skies and white clouds. The slim filter frame rotates to adjust the exact amount of polarisation required.