The No.200 set contains 5 A200 HSS centre drills, with sizes between 1.00mm to 4.00mm. They are used to produce 60 centres in components, where subsequently, manufacturing operations are to be carried out. The No.225 set contains 5 A225 HSS centre drills BS1 TO BS6. These have been designed with spiral flutes, of various lengths and forms to produce smooth centre holes to suit most applications. Features and Benefits Drills create quality, smooth centre holes Various lengths and forms of drill Supplied in durable plastic cases Contents DOR0253760A - 1 x 1 to 4mm in increments of 1.0mm DOR0253760B - 1 x BS1 to BS5 Material Applications Cast steel Cast iron Steel Standards BS328: Part 2:1986 DIN333A ISO866 ISO2540 ISO2541