The Hoya 49 mm C2 Blue Cooling Color Correction Multi-Coated Glass Filter is a precise optical accessory for photographers who require accurate color temperature adjustment. This 49 mm diameter filter provides a cooling effect of 200 Kelvin with a MIRED shift of -20, adding a subtle blue tone to correct warm lighting conditions. Made from high-quality optical glass with multi-coating, the filter significantly reduces reflections, glare, and ghosting while maintaining over 97 percent average light transmission for optimal image quality. The multi-coating enhances contrast and clarity while offering lasting protection against scratches and surface damage. This color correction filter is particularly useful when working with tungsten-balanced film under warm artificial light or daylight-balanced film during the golden hour. It excels in scenarios that require color temperature adjustment for natural-looking results, including indoor shots with incandescent lighting and outdoor shots with warm ambient light. The filter thread measures 49 mm for compatibility with corresponding lens diameters. Professional photographers appreciate this tool for its reliable performance in achieving precise color balance and preserving optical integrity under various shooting conditions. Its robust construction ensures long-term durability, while the advanced coating system maintains image quality by minimizing optical aberrations. This filter serves as an essential component for photographers demanding accurate color reproduction and consistent performance in different lighting environments.