The Mueller-Kueps Carbide Tip Drill Kit, No. 562 600, is designed to drill out extremely hard materials such as bolts with high tensile strength (up to grade 12.9 metric and grade 8 imperial), burnt in studs, and more. The high-quality drill bits also offer ideal wear resistance. The kit comes in a durable wooden box, featuring four sizes: 3mm, 4mm, 6mm, and 7mm. Other sizes are available upon special request, the company said.