Use it by fitting in a flex wrench. The biggest advantage is that the box can be used where the height is lower than the usual ratchet. Because it is locked, there is no worry that the box will be left behind by the bolt, and since the upper part can be rotated by hand, it can be turned speedily. If you have a wrench with a switch you may be able to use it more conveniently, but because it is something like a help item when you are in embarrassment as an application, is this enough? But I wish it was about 1500 yen if it was a bit expensive as an item to help. So the star is 4.