Tungsten worm weights are insert free and made of 97% pure tungsten. Made with quality in mind. They come with an insert free line guide so your line will last with no scratches. The tungsten worm weight also has a chip resistance painted head so it will last a long time. Denser then lead tungsten gives this weight a slimmer profile to punch through heavy cover and give you the feel for the bite. Works great around heavy cover such as logs, weeds and much more.