William Salchow began making rosin in his shop nearly 50 years ago, and the recipe for his rosin has remained unchanged since then, maintaining a strong reputation among musicians. The rosin is crafted by Salchow & Sons, a highly regarded artisan bowmaker based in New York City, using a recipe perfected by William Salchow and his family over half a century ago. It is a professional-grade, pure rosin with no additives, designed to deliver a smooth tone with low dust and residue.