The PROMASTER Digital HGX Circular Polarizing filter allows you to remove unwanted reflections from non-metallic surfaces such as water, glass etc. It also will enable colors to become more saturated and appear clearer, with better contrast. This effect is often used to increase the contrast and saturation in blue skies and white clouds. The PROMASTER Digital HGX Polarizing filter does not affect the overall color balance of a shot. PROMASTER Digital HGX filters are the most advanced optical filters available today for digital photography featuring: Next Generation Digital Anti-Reflection Multi Coating ? Specially formulated to minimize internal reflections created by CCD and CMOS sensors in a digital SLR. REPELLAMAX? Element Resistant Coating ? This EXCLUSIVE PROMASTER coating repels moisture, fingerprints, dust, dirt, and grime to ensure the sharpest images possible Hardened Optical Glass ? Ultra hardened optical glass resists surface scratching and stands up to the most intensive use. Low Profile Anti-Reflective Frame ? Ultra thin low profile frame helps prevent vignetting on super wide digital format lenses. The satin-like smooth finish helps to minimize reflected light. Black Rimmed Glass ? The outer rim of the filter glass is treated with a special black-ink.