2 1/8 or 54 mm , nice to find another rotary head here.
At my work we have a couple of 4" Impact sockets, 1 inch drive, they weigh so damn much the could be weapons. Used a lot on big heavy equipment nuts.
The sizes range from 2 up to 4 in 1/8 inch increments with a couple of random 16ths.
We also have special axle nut sockets up to 5 and something inches.
The biggest wrench I have is 2 1/2", and the biggest socket is 2 3/4, not counting my axle nut sockets. I also have the same 40" ratchet shown earlier. I actually bent the handle once and had to have it replaced, but I had a 5' cheater pipe on it.