This is a UV Coated replacement flashtube for the older Powerlight monolights, models PL375 and PL750.
UV flashtubes have a yellow appearance, and they counteract the excess blue 5700° or higher output of non-UV coated flashtubes. UV Coating lowers the color temperature to 5500°, which is the color of noon daylight on a clear day.
UPC: 689670080323