There was a fella in Portland Oregon who made these. He made saddles for Johnny Marr that were Bakelite I believe. He was making them from Titanium and since he is a good friend of mine he made these brass ones for me as per request.
Better sustain, less of that Jazzmaster plinky plunky thing, not unlike those absolutely lovely StayTrem ones that are hard to get here. Strings stay in the slots even without those awful Buzzkill devices! I love brass saddles for tone.
Natural playing wear, no soaking in water for rust "relic" nonsense. I just oiled everything today. This lived on my old Jazzmaster for 2 decades and I sold that guitar recently. Looks great on an old guitar.