Material: 45# Carbon Steel, with quenching treatment.
Includes 4 sizes(6mm, 8mm, 10mm, 13mm) in one plug cutting set.
For the hand electric drill and bench drill, recommend bench drill, centering easily.
Carbon steel is durable, precision production, smooth surface, suitable for bench, speed not too fast, otherwise will smoke, charred.
Make plug with largest bit to fill hole made with middle bit, make plug with middle bit to fill hole made with smallest bit.