Feit 125w diffused mercury lamp

Kind of an unusual lamp - it is marked for an H38 ballast but rated for 125w, so is likely designed for those yard lights that overdrive a standard 100w lamp, rather than a true H44 ballast. Also, there is no phosphor, just a diffuse coating, so it gives the colour of a clear-bulb mercury lamp. I sent this one to my friend in the U.K. to use on a common 125w ballast there.