Made with high quality natural resin encased in a sturdy finished wood block with an easy to open slide box,this brand of rosin is an American tradition as apple pie. The Super Sensitive String Co was founded in 1930 as a family owned and operated business. It's focus has always been to furnish the best strings and accessories to musicians,music students and music educators. Long lasting. Mini size is great to place in stockings,for traveling,or having a spare in the glove compartment!