This Industrial and Scientific jobber cobalt drill bit is definitely the best I have used so far. Through trial and error, I found that this bit drills through tough materials easily and lasts longer than any other bit I have used. It's perfect for professionals who need durable and reliable drill bits. The only downside is the price, but it's worth the investment for its quality. Overall, I highly recommend this product to anyone in need of a high-quality drill bit.