I use these drives on a daily basis and all day long, up to a 12 hour shift. And I use them in a Makita brushless impact gun. So long story short, I break them on a regular basis and need to find replacements as cheaply as possible. These fit the bill. Since I go through about 3 a month, I find the cheapest replacements I can find. Thank god for Amazon. And it has nothing to do with the quality of the bit. I use them and use them very very hard. That's why the short life span.