It's a great lens, and I just don't use it. It's about the same size and weight as any other AF 300/2.8, and is as good optically too -- in fact at 300mm, I could not tell it from a Nikon 300/2.8 prime and why I went with it. It is the model immediately prior to the latest model that as far as I know, had some cosmetic changes only. Lens is in excellent condition optically, mechanically and cosmetically, basically looks and operates as new. Included are the case, and also BOTH Sigma dedicated APO converters, a 1.4x and 2x. With the 1.4x, there is virtually no detectible image degradation; with the 2x there is a teeny bit of loss near corners wide open, but even that is barely noticeable. It will even make images with both converters stacked, but will not lock AF on my D810, though with this combo the images do show visible loss of quality. OS works surprisingly well, and I am able to get exceedingly sharp images hand-held at 300 and 420 with the 1.4x, though I need a tripod or monopod at 600 with the 2x to get critical sharpness.
Asking $1995 OBO.