The D Addario Natural Dark Rosin with Black Rosin Guard is a high-quality rosin designed to enhance the performance of stringed instruments. The natural dark rosin provides excellent grip and produces a rich, warm tone. The included black rosin guard is specially designed to absorb shock, preventing the rosin from cracking or breaking. With its easy-to-grip design, the rosin guard ensures a secure hold and makes it easier to apply the rosin to the bow. The rosin is magnetically secured in the dishwasher- and sterilizer-safe holder, providing convenient storage and protection.