QuartzLine filters are made of 99.9% pure fused quartz for unrivaled durability and optical clarity. These single lens element, fused quartz filters produce a very low refractive index of 1.46 and offer outstanding temperature stability. The over-engineered brass filter frames thread on smoothly and are built to withstand your most rugged adventures. Featuring optical coatings for a hyper neutral color profile, near perfect target transmission, and multi coatings for enhanced scratch resistance, water resistance, anti-reflectivity and reduced vignetting in wide angle shots, QuartzLine filters let content creators bring true-to-life colors to their final product, from the most extreme locations on the planet. Each QuartzLine filter includes a microfiber lens cloth, soft filter pouch and a filter hard case.