I purchased this set of three step drill bits for about $10 on January 30, 2017. I have used them several times for drilling mild steel over the past 20 months and have had no complaints. Fast forward to today 8/20/2018 and I found out how good these beats are. I was repurposing an old bed frame and had to drill 24-3/16" diameter holes. Anyone who has worked with old bed frames knows how notorious they are for their hardness due to their high carbon content. I burned 6 twist drill bits and only made 4 holes then i remembered these bits and gave them a try they drilled 20 holes and are still sharp so yes i can definitely say these stepped bits are worth the investment.