Sorry about this, servicing the car tom but I can't see the sump plug from looking under the car. Can anyone tell me whether it is a hex key, bolt head etc. and also what size ? Don't want to put the car up and then find out I don't have the right one. Also, whether or not it is a straight fit back in with the old plug or if there is a copper washer etc. on the back. cheers, G.