Post hole digger : 

1. it can match with tractor rear 

2. it can do 30-100cm diameter hole, the hole depth can be 10cm -80cm 

3. it need the PTO shaft to match with tractor , the speed is 540r/min

4. the drill can be changer, the meaning is you can just buy one set machine, but purchase different size drill, you will make different size hole !