I think the "BP" identifies it as "Bromide Paper". Their Bromportrait paper carries the same designation. I believe these may be the last true bromide papers on the market, now that the Kentmere Bromide has (I think) been discontinued by Harman?
I've used the Unibrom paper a little. Still have some of all three grades in my darkroom. Used Ansco 130 developer and selenium toning. I thought it looked really nice.
But it did seem noticeably higher in contrast per grade than I was used to. More like 3, 4, and 5 instead of 2, 3, and 4. I just diluted the 130 more.
The current ISO range numbers say this shouldn't be the case, at least when compare to the Ilford Gallerie data sheet, which still lists all four grades, but that was my impression.
As I recall it does require a deep red safelight. I use 635 nm LEDs filtered through Rubylith.
[Edit: See post #82 on the next page...]
Ken