Nose and drive.Not got these then it is not a Plummer. A plummer is'nt and out and out digging dog some are some not.Some lines are are more prone than others. Admittdly most Plummer owners these days want a ratting dog not an earth dog. Mine are all coalville lines and they do the job for me,they suit me. Plummers were breed to be a jack of all trades,which they are.