Big ass heavy duty all cast iron clamp. Could squeeze the buggers out of the green guys head during lunch for fun! Adjustable up to about 18" or so I don't really want to go measure right now. It can also slide back and forth about 10" on a lead screw while it's bolted down. It's pretty sweet. I work alone so nobody to torture around here. My loss your gain!
Total size is it's sitting on a full size pallet in the picture