ProMaster 39mm Circular Polarizer - Digital HGXProMaster 39mm Circular Polarizer Digital HGX ProMaster SKU: 1779 Helix SKU: PR1779 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