FL is fluoride-ion glass, which has special optical properties. It was introduced in Zeiss' Diascope spotting scopes.
Also, the Victory Diavari 6-24×72 T* FL now features Zeiss' revolutionary Rapid-Z Ballistic Reticle Systems, ensuring better accuracy on long-distance shots.
This magnum-sized scope, originally built for professional marksmen in the military and European law-enforcement agencies, is designed for American shooters who require the best low-light performance.
Contact Carl Zeiss Optical Inc. at (800) 441-3005 or www.zeiss.com/sports.