99.9% Pure Fused Quartz glass element with a base refractive Index of only 1.46 for razor sharp imagesSingle Element 3-Stop Neutral Density with built in Polarizer eliminates the need for filter stacking82mm Rugged Brass Frame / New optical coating technologies achieve near perfect target transmission while maintaining a Hyper Neutral Color profileAbrasion Resistant and Hydrophobic coatings increase surface hardness and make cleaning easyIncludes QuartzLine Filter, Soft Filter Case, Hard Filter Case, Microfiber Cloth, and a Lifetime Warranty