Was contracted to do an energy efficiency upgrade at a shopping mall in south Milwaukee, this mall used 30 black "pendant" type HID fixtures that hung from the ceiling, the ballasts were remote and mounted to ceiling beams. At first I thought they were just dim, greened-out coated 250 or 400w metal halide lamps nearing EOL. But was blown away when I got up on the lift to disconnect the fixtures. ALL of these pendants contain Sylvania 400w clearbander mercury vapor lamps! Etch specifically is "H33GL-400/DX". Only one fixture contained a newer Plusrite 400w mercury lamp. I have a feeling these lamps are original to all these pendants, arc tubes are all quite blackened. There is an "81" under the 400 on the lamps etch...date code maybe??. These fittings were all replaced with chinese 100w induction fixtures. Ballasts are all potted F-Can type that have been painted over with no info on them. They are however mercury (H33) only ballasts as a 400w metal halide just cycles on them.
Quite a find!

Lamp

etch closeup

Wonderful long-lived classy clearbanders! Pic of the Fcan ballasts anywhere? Hope you kept some

81 for these lamps would be September 1978. That's a pretty long run. Nice find!