Made from high-speed steel, these bits are heat-resistant, durable, and have a long lifespan. They are ideal for drilling into thin plates of aluminum, copper, wood, and PCB. They are not suitable for concrete, masonry, and stainless steel. The split point and twist design increase cutting speed and easily self-center to prevent wandering. The sharp and high-hardness spiral bits make drilling easier and more efficient. Keep them cool and smooth during use to prolong their lifespan.