found at DigiDirect
The HOYA 49mm CIRC-POL HD MkII Filter is a high-quality circular polarisation filter that prevents reflections on non-metallic surfaces, such as water or glass. This increases the saturation and contrast in your shots. Because this is a circular filter, you can adjust the strength of the effect by turning the filter. The glass of this filter has been chemically improved and is no less than four times stronger than its predecessor. It is also provided with a 16-layer anti-reflective multi-coating that makes the glass water- and oil-repellent, and scratch- and stain-resistant. Thanks to the thin mount, you won't be bothered by vignetting that can occur when using wide-angle lenses.