Mettler Thread Silk Finish Cotton 40 164 Yds Color 9136-0350 Summer Sky SILK-FINISH COTTON 40 is made from 100% long staple, Egyptian cotton and is excellently suited for patchworking and quilting. This thread is slightly thicker and therefore shows more beautiful decorative effects. SILK-FINISH COTTON 40 is also perfectly suited for sewing and because of the mercerization process has a very reduced shrinkage and is heat resistant.