I have seen it all now!!! While fishing this weekend I was looking thru my tackle box when a friend of my sons was rummaging also looking for a weight when to my amazement he pulled out a spark plug!!! I thought what the H3LL!! He told me that he fishes in lots of rocks and they just dont hang up and hold real well. He had plugs from lawnmowers to tractor plugs. He said he gets them free from mechanic shops who just throw them away. Has anyone ever seen this before? I am headed out to a very rocky spot that I always get hung up to try them!!! Will keep you posted. A great weight and also helps keep them out of landfills!!!