Found the answer here: Coated Lens for a Solarforce L2P?
Posted by Hank Wang: “AR coated lens does not come with a brand, the important thing is the quality.
Try the lens we offer, with double AR coated, and fits Solarforce and Surefire flashlights fine.
http://intl-outdoor.com/28mm-ar-coated-glass-lens-p-840.html”