The inside of the gooseneck is actually a spring which is made of a high-strength steel (stainless steel can also be used if the gooseneck will be exposed to moisture). This is what gives the gooseneck it’s strength and flexibility. Then a soft galvanized iron wire is compressed into the gaps of the spring coil (stainless steel or brass can also be used). This is what gives the gooseneck it’s stiffness – or ability to hold it’s position.
Many factors determine how stiff or rigid a flexible gooseneck is as well as how much weight it can support:
The material used for the inner spring and outer wires
The outside diameter of the inner spring and outer wires
The the size of the spring itself (inside/outside diameter).