A six inch diameter rotary table, it looks to be unused. Substantial cast iron construction, it can be clamped to the milling table horizontally or vertically.
The bit I haven't seen before is the dividing plate mounted behind the operating handle - it looks like hald a dividing head without the sector arms grafted onto a rotary table. No doubt those more expert than I will write in and tell me exactly how (and why) you would use it.
Weight 32 pounds