IMPROVED PROTECTION PERFORMANCE AND DURABILITYHD nano Mk II CIR-PL coatings have the advantage of being the hardest, scratch & stain resistant coatings available from any manufacturer. Over time normal filter coatings can be easily damaged by repeated cleanings by wiping with too much force or abrasive cleaning cloths. The HD nano Mk II coating are 200% harder for increased longevity and greater protection.HIGH TRANSPARENCY POLARISING FILMHD nano Mk II CIR-PL high transparency polarising film has 25% better light transmission than standard polarising film used in current photographic filters. This translates to nearly 1/2 stop more light entering the lens while yielding the same polarisation effect, maintaining the colour balance of a standard circular polarizer while improving contrast and clarity.CONTROL REFLECTIONSThe HOYA HD nano Mk II CIR-PL filter allows you to create unique effects in your photo which are not achievable through editing software in post production.One such effect is the controlling of light reflections on glass or water surfaces. The HOYA HD nano Mk II CIR-PL allows you to control light waves entering your lens, through the filtering of all polarised light. This allows you to see below surfaces of water. This effect is also great on glass surfaces. By removing reflections, you can look through the glass and into interiors.ENHANCE CONTRAST AND COLOUR SATURATIONPolarised light is not limited to surface reflections, but light shining directly from the sky is polarised too. Air molecules, moisture and dust scatter sunlight, and this light can be filtered out with the HOYA HD nano Mk II CIR-PL. This allows you to greatly increase the contrast of the sky, removing haze, and enhancing blue hues.Specs:- Hardened Glass: Yes- Hardened Coating: Yes- Water-Repellent Coating: Yes- ND Number (Filter Factor): 2.2- f-stops: 1.1- PL Film Type: High transmittance film (by 25%)- Frame Material: Aluminium