FF Sveppur and Svepper Slug are made for one reason. To balance off the Shadow flies. We want our flies to fish right away when it hits the water, and we want our flies to be well balanced. With the new Sveppur family its now possible to give your 3mm plastic tube the perfect amount of weight to do that. 10 in each pack The Sveppur weight is 0,14gram The Sveppur Slug weight is 0,28gram They come with a thind liner..