I bought one of these wrenches to keep in my backpack so I can remove my single speed wheels in the event of a flat tire and was disappointed with the outdoor handling - end of the wrench. There were obvious machining marks, and the slot that the 15mm nut would fit in doesn't have flat sides parallel to each other (they appear to be wavy due to poor machining). I emailed Amazon for a replacement and my second key looked the same. The key works fine but I just expected better quality.