The mercerization of Mettler cottons creates that beautiful silk-like sheen, high breaking resistance, color fastness and optimal elongation that you look for in a high quality thread. Use Mettler's SILK-FINISH COTTON 50wt with confidence to create your heirloom quilts, custom garments and creative projects.

This is 100% cotton thread.  The "Silk Finish" refers to the silk-like sheen of the thread.