one or more concentric circles around the collar 1 9 it will be recognized that barbs can also be placed both on the collar 1 9 and on the second portion 1 11 of the anchoring tube 1 4 if desired in some embodiments the collar 1 9 and barbs 1 10 are formed of plastic e g silicone or ceramic and can be molded around the neck 1 2 see fig2 a if desired in one embodiment a very flexible arrangement can be formed using flexible conductive fibers the multi filament conductor 1 6 can include many strands of very thin conductive fibers for example the fibers can have diameters in the range of 1 to 500 u03bcm preferably in the range of 10 to 25 u03bcm any number of fibers can be used to form the bundle including several hundred e g at least 100 and up to 500 or more fibers one example of suitable fibers are thin stainless steel fibers which can be bundled together to form the conductor 1 6 at one end the fibers are connected e g welded to the contact 1 1 at the other end the fibers are connected to the connector plug 1 8 in one example of a method of making such a connection the fibers can be passed through a metal tube e g a platinum tube and optionally the tube can be smashed against the fibers the fibers are welded.