The Master Series 170mm Circular Polarizing Filter is made to fit the the Benro Master Filter Holder and has a knurled edge for easy polarization adjustment. Adjusting the polarization enables elimination of unwanted glare and reflections on water, glass, and other reflective surfaces. This filter features ULCA multi-coating to render more richly saturated colors, plus NANO WMC protective coating to resist oil, water, smudges, and abrasions when working out on location in harsh environments. It is designed to be used with Benro filter holder system, and even works with ultra-wide lenses. This 170mm filter conveniently slides into the first slot on the filter holder.