Made with schott b270 german optical glass, the finest available, precisely ground to ensure brilliantly sharp images with no ghosting Hardened glass makes this filter twice as strong as similar filters without hardened glass Ulca multi-coating decreases flare and significantly reduces chromatic aberration (average transmission 99.0% 420-680nm) Nano wmc multi-coating is scratch resistant and repels water, dirt and oil from smudges and fingerprints, making the filter easy to clean Irnd coating helps maintain faithful color rendition by eliminating blue or warm color shifts caused by unwanted infrared and uv light