The needle has a single tongue that has twine that feeds out of the needle end. The 'u' shape of the needle keeps the twine from slipping. These needles are very good for unwinding string. If you try to fix nets with your fingers it would be much harder than using a needle to do the job. The shape of a needle is fool proof because it makes it so your fingers don't slip. Some needles have a hole in the top so the twine can be spooled through the little hole. You can load it by taking more twine and wrapping around the needle until it is full.