"There will be an H502 (XM-L, <2.9"), slated for release in Q4 this year. The H50 has a negative meniscus lens. The H501 uses a positive meniscus lens. Both are made of polycarbonate. The H502 will use a plano-convex lens (optical grade glass, tempered, AR coated on both sides). We'll have a link to a google docs sheet in 1 or 2 days for all current and upcoming models."