3/4" Snap-on impact with 1/2" inlet. I bought this impact for one job and never used it since. It is around 1200 ft/lbs of torque, maybe a little more. The guy I bought it from said he only used it once. It has been riding in my service truck for about a year. I finally realized I would probably never use it so passing the savings onto someone else. I actually wiped of the snap-on logo when I was cleaning the dust off of it. OBO