Hiya balugamoo,
The modern day Shark Shield uses the same technology that was patented by the Natal sharks board when they created the original Shark POD.
The Australian company, SeaChange Technology, which is now called Shark Shield pty. ltd. licensed the electronic wave-form technology from the sharks board.
So they are essientialy using the same method / technology deterring sharks with the Shark Shield being the modern day version of it.