Silicone rod, (Recommended):
Shaft with silicone rod inside—In this case, the shaft cannot be fixed, if you bend it up or down and suddenly release it, the shaft will come back into its first position. This is because all shaft is made from silicone. The device with a plastic rod can be fixed, you can bend shaft down, release it, and it will stay in the position.
The rod is made of plastic and is very light. Therefore, you will not experience any problems in airports when going through the metal detector. The rod may exhibit some noise when flexing. This is due to the friction of the plastic ball joints. (The flex rod is a plastic rod made up of many small ball & socket joints.)
Rod is very sturdy and durable. There are no cases that it breaks or gets damaged in any other way. In some cases, the ball comes out of the socket connector. But it can be returned into the original position by pressing ball to socket joint. Rod joints can pop out (In that case, you need to strongly press the popped-out part to fix it in place and move the joint back into the first position).