The adapter series has a 6 angle part that can be operated with a variety of wrenches in the perimeter of the insertion angle.
If the rotation axis tend to fall over, such as when high torque work in deep places, you can use a spanner or a glasses wrench, etc., to make it stable as driving with a T-shaped handle.
6644A-KH cannot be installed on socket rails.
The adapter that reduces the insertion angle may damage if torque is applied with a handle with a large insertion angle.
Please be careful of overtorque.