I thought I'd just post up a picture of a Jika rig because hits keep coming via google searches and the photo google displays is all wrong. I wouldn't want people to think that I don't have a clue what I'm on about hey! ;-)
The beauty of the Jika rig is that you can choose your hook size or weight to suit the depth or conditions you are fishing, just like you would a jig head, this makes it a very versatile method.
You can buy the rigs already made up for you, but I find those pointless and expensive. I also find the bespoke weights are too often expensive and neither do they minimise losses or often come in the weights I need, any old bomb will do. You just put a split ring in the top of the lead, a split ring in your chosen weedless hook and then join the rings together. Next, rig your chosen soft bait, clip on your rig by the hook ring and away you go, a simple and very effective way of rockfishing.