The cobra system uses a static, specially designed rope with a relatively open lay. The system is made dynamic by the insertion of a rubber shock absorber. This is pushed inside the rope making it look like a snake after a big meal. as a stem/branch moves and puts more tension on the system the bump is squeezed by the rope trying to equalize the tention across the whole of its self.
It is a dynamic system, but with relatively little stretch, enough to let the tree react with growth but restricting it enough so as to give support.
Very clever and very easy to install
