Yes, PFO is the name of a manufacturer, but Scott and I disagree on the definition of HQI.
Perry Jones says that HQI means High Quartz Iodide in the U.S. lighting industry but it means Mercury (Hg) Quartz Iodide every place else in the world. (P.S. -- I just located an American source that calls it Mercury Quartz Iodide, too. See the first sentence at the top of page 194, The Reef Aquarium, Vol. 1, by J. Charles Delbeek and Julian Sprung: "In the Osram HQI (mercury quartz iodide) Powerstar, a glass lens must be incorporated in the fixture to protect the bulb from water splash, and to prevent the passage of too much ultraviolet light. These bulbs come in double or single end formats.") -- Hmmm... I guess that counts as an American and a Canadian reference.
If you will look in Fossa & Nilsen's Modern Coral Reef Aquarium series, you will see that they call every metal halide lamp HQI, including 5500K and 6500K lamps.
The European manufacturers use pulse start and the American manufacturers use probe start and all of the European DE (double end) lamps require pulse start (so-called HQI) ballasts. The new 250w 20,000K HQI mogul base lamp also requires an HQI ballast. The 400w 20,000K HQI mogul base lamp can be run on either ballast but it does better on an HQI ballast. An electronic ballast can be substituted for an HQI ballast, AFAIK.
I think the confusion over here lies in the fact that most hobbyists think that HQI refers to double-end lamps only.