Mettler 60 520. SILK-FINISH COTTON 60 is your perfect piecing, fine stitching and fine embroidery thread. Quilt, sew and embroider with confidence knowing that SILK-FINISH COTTON 60 has been mercerized to add strength, and color fastness, while giving it that Mettler silk finish. The high breaking resistance, shrinkage control and ironing capabilities make COTTON 60 a top choice among quilters and sewists. Tex 23. Manufacturer recommends needle size 70-80. 100% Cotton. Old color number 240-0520 or 240-520.