Recently acquired this brush and was having a hard time finding information on it. Wanted to see if anyone here could provide more information or perhaps confirm if this is a vintage Simpson? I don't have a set of calibers handy, but this is one of the largest vintage brushes I've ever seen, it keeps up with modern brushes so I'd estimate knot is 28-30mm+. A quick google search shows that I. Maglin. & Co was a high end store from California. Hoping someone can help out!