If ur fishing rock marks regularly u probably use them,they are easily made,get some rubbery plastic,i use clear icecream tubs,or old lunch boxs,cut out little kite shapes about 3-4",long and 2" wide,then bend them in the centre from top to bottom,then heat a small nail and put a hole top and bottem so u can put them on ur rig above ur lead,they work really well,they do reduce ur distance a bit but u should get ur rig back if u cleared the rocks in the first place!