I recently purchased these drill bits for my metalworking projects and was impressed with their durability and versatility .As my tests showed, they effortlessly drilled through aluminum and plastic, making them perfect for any industrial and scientific applications. The titanium coating also ensured that they remained rust-free and long-lasting, making them a wise investment. The only downside is that they ARE a bit pricier than other drill bits on the market but the quality more than makes up for it. Overall, i highly recommend these drilling and cutting tools..