These bits are a little challenging to review. On opening, they appear to be fairly well made with no obvious defects, and in a case that seemed reasonably well made considering the kit's price point. On use, the bits cut well, though perhaps not as smoothly or as refined as some higher quality ones I have. After the first use I did notice one of the bits' finish was noticeably degraded, likely indicating a production quality issue on that bit. I did see another reviewer mention issues with size fit on extensions, and wanted to check for myself, and there is a bit of a problem; I did find two that were too large, and three that were small enough they had play. The other 11 fit well. This to me indicates production quality again is a challenge, and something I would be concerned about longer term. These bits simply don't seem to be super durable given the issues identified. That said they are good at their price, and for casual users.
Keith northcott 
