Royal Oak Profi-Line Viola Rosin is designed for the frequent player. It is formulated for less frequent rosining, greater yield, and a clear, pure tone. Because if it's less bow abrasion there is less string fouling. This rosin is all natural, non-allergenic, and engineered to be non-agressive to bow and strings. Established in 1996, Royal Oak's German-made rosins and cleaners are fast becoming a favorite in the industry!