1-14mm HSS Cobalt Jobber Twist Drill Bits Set for Stainless Steel Hard Metal. Size: 1mm – 14mm. Material: M35 high speed steel. Compatible equipment: hand drill, cordless drill, bench drill, etc. Uses: suitable for drilling thick cast iron, stainless steel, aluminum alloy, non-standard metal, wooden plate, etc. 100% Brand New And High Quality. Absolute guarantee of high quality and inexpensive!