This is a very impressive lens. It is really huge and heavy. The filter siize is 77 mm and the lens weighs over 2.5 pounds. It is also built like a tank.
The lens design is based on the famous Olympia Sonnar 180/2.8 design by Carl Zeiss which was first introduced for the Olympic Games of 1936. It was the fastest lens at the time and was opening new fields for sport and action photography.
I haven´t had a chance yet to test the optical performance of this lens but will post my results as soon as I get a chance.