Spring loaded T steel fencepost pounder that weighs roughly 17 1/2 lbs, I.D. 2", O.D. 2 1/4" ( rough measurements ). It is claimed the spring loaded pounders are easier to use as they self bounce back up after each strike. A couple of decades ago it cost about $100. It has always been kept inside when not in use and was not used very much - just around our yard. Price is firm as I think it functions as good as new.