Material: Drill bits are made of high speed steel 4241, the black parts are made of #45 steel
Feature: Drilling hole depth can be adjusted by loosening and tightening the black parts, known as drill bit rings
Attention: Only for drilling screw holes in wood and plastic; can not drill holes in steel material
Size: 1/8 inch, 9/64 inch, 5/32 inch, 11/64 inch, 3/16 inch, 13/64 inch, 7/32 inch
Perfect for the bench drill, hand drill, etc