I'm having trouble drilling holes in my polished concrete floors to install sleepers for new wood floors. (Tore out the carpet). I bought Lowe's fanciest for $8 and was told it would last a long time and use water when drilling. NO! I ordered a set of these as a backup. Package opened and used. clasp and clasp. DONE. I couldn't believe it. I finished a hole that no other drill could do and made two more in just a few minutes. I needed a regular DeWalt drill bit. Don't let the price fool you. You are wonderful. I will be buying a few other sizes from the same company!