ALLOWS REMOVAL OF SCREWS WITH DAMAGED HEAD, SUITABLE FOR INTERNAL HEXAGON, T-STAR (FOR TORX), SPLINE SCREWS (FOR XZN) ETC., EXTRACTOR BITS WITH HEXAGON DRIVE IN FOLLOWING SIZES: 3- 4- 5- 5.5 - 6- 7- 8- 9- 10- 11- 12- 13- 13.5- 14- 15- 16- 17- 17.5- 18- 19- 20- 21- 21.5- 22- 23MM, ALSO SUITABLE FOR SCREWS WITH CORRESPONDING INCH DRIVE