haa0012 's Japan Review

It is good because it comes with a tool that is useful for attaching O-rings.

It is easy to attach just by having this.

This is a tool that is not often used, because it can be attached by simply inserting the ring from the narrow end of the shaft (flight side) and turning it in the direction of the screw.
If the shaft has a special flight fixing structure, it is not possible to insert the ring from the flight side, so this tool is very useful in such cases.