Not a rubberset brand brush. Looks fairly old. I'd put hair conditioner on the bristles, they look rather dry.
To moisturize the bristles, following your advice, I put some olive oil that I make from my plants. Then a nice shampoo!
Multiple brushes said that on them , BUT , it didn't mean they were rubberset branded brushes.. It only meant they were set in rubber....
I apologize, I didn't mean the brand but the typology, the brand should be T.S New York. I edited the title
No need to apologize.. That would be very easy to get "mixed up".. 1 thing I have read previously ( whether true or not or just to make their brushes sound better) is that brushes that stated "set in rubber " were supposed to be higher quality than those that didn't...
The alternative glue option at that time was wheat paste glue, which pre-vulfix merger, was still what Simpson's used. No clue if they still do.
