I bought supplementary 1.5 mm across flats, but it is somewhat eccentric when I try it. So when holding the tip 10 mm with the chuck and rotating it the tip of the handle was swinging 7 to 8 mm. By the way, the previous 1.5 mm opposite side purchased by another shop was about 1 mm shake, 1.27 mm across from the side which condition should be bad, and the swing was about 1 mm. It may be a variation, it may be this kind of thing because it is a working tool, or it is unclear whether it is trouble of product management, but I do not want PB products to be such a disappointment. It was able to improve somewhat by looking at the mind.