The new low profile Circular Polarizer takes advantage of Hoya's new patented optical glass technology to create a hardened optical glass that is thinner than the normal optical glass. This allows the overall thickness of the filter to be reduced to avoid vignetting when used with ultra-wide lenses. The Hoya Super-HMC low-profile frame is a slim 5mm, making it the same size as a regular Hoya filter frame. Standard Hoya Circular Polarizer frames are 7.5mm thick where other manufacturers filters are as much as 10mm thick. Another advantage to the Super-HMC Circular Polarizer is it has normal front filter threads, meaning a normal clip-on style lens cap can be used. The Super-HMC Pro 1 Circular Polarizer has a 6 layer Hoya Multi-coating, the most used in industry, applied to the front surface of the filter to greatly reduce the chance of lens flare or ghosting caused by reflections.