This is an older post hole digger / auger with a 9" diameter x 48" long bit that has a new spiral tip point. I believe it is an older Speeco Model 70.
It will work with compact tractors (Kubota B Series, John Deer 2xxx Series) and larger, but the 3 point hitch bracket is 31" wide, so it may not work on the sub-compact (BX / 1xxx series) tractors - you'd have to measure the width of your 3 point arms at the pin mount location.
Last picture shows that all components separate for easy transportation and/or storage. I forgot to include the "handle" that is used to position the auger when seated on the tractor.