It might be a Traub. I've a Traub 60 set up, takes up to 2 1/2": irrc, that looks very similar. Sort of thing that if you need it, its a bargain and 4x the price....but not many will need it. Hard to find info on. I suspect they were a thing pre cnc when a lot of production was done on turret lathes
I've not set mine up. I have rubberflex and 2J's and just haven't the need for say a 2 3/8 collets.....but if you buy it, well, "then you have it" lol