Well, I'd ask a Pleiger tech. But
from what I read here, Pl-22 is the product developed by them to be used in the place of PL-15, which is a Bayer license.
It also says that the 22 is available in colors, but no such mention is made of that about the 15.
This information, however, is about the plastics themselves, and not specifically squeegees. Myself, I haven't used or seen a light brown blade since they were real rubber.
