The lineman here put one of those on one of the 250w M250R2s here. It was on a 150w Cooper OVZ but the replacement M250 was one with flat glass on a walking trail, so he removed the glass and put the Cooper's refractor in its place so more light would shine on the walking path. I expect it will eventually turn brown
Ah they're not using glass anymore? Here NGrid uses this refractor for the 50, 70, and 100W HPS M-250R2s. Only the 250W HPS ones have glass for an original refractor.