That is my famous (or infamous depending on how you look at it) Negrito Hunting Bolo. 9 inches of leaf spring steel with melted down brass cases for the guard and water buffalo and soda can aluminum for the handle. Cost me all of $2.50 WAY back in 1975! You wouldn't believe what I have used it for. It's been used so much that I don't think it will rust any more. When it would start to rust I would just start jabbing in into the ground until the rust was gone.