(Philips?) 175w Mercury Vapor

This particular one did duty in an Electripak yardblaster for 20 years, most of those spent in non-use, hence the almost-clear arc tube. This one still works VERY well and the only reason I took it out of service lighting my backyard is because I was given another identical lamp and I wanted to test it and ended up just leaving it in there. There's no installation date scratched on the base though. I bet this lamp was original to that light. It has the characteristic arc tube frame rattle, so easily that once upon a time when I had the light mounted indoors the bass from the stereo would make the frame rattle!
Although not a Lifeguard I'm sure this lamp is still better than the ones made today. Most of the use on this one has probably happened since December 2011, when I was first given this lamp and the fixture it came in. Can someone confirm this is a Philips judging by the design features? Because there's no other etch or visible markings anywhere.