Kolstein Bass Ultra All-Weather Rosin For Upright String Bass Kolstein & Sons, Ltd. produces this outstanding upright string bass rosin using their Ultra Formulation Supreme recipe. Very minimal powdering and excellent grip equate to quick response and consistent sustain for both the veteran and beginning bassist. Kolstein Ultra Formulation Supreme All-Weather Bass Rosin is world famous for its low powdering and smooth, easy bowing. A good rosin for players with respiratory difficulties.