Heartcosy Grade 6A Mulberry Silk Comforter – Organic Cotton Shell, All-SeasonThe benchmark for silk comforters built to a standard, not a price point. At $289. 99, this is Heartcosy's flagship silk comforter. The premium pricing reflects two choices that most silk duvets at this level don't make simultaneously: Grade 6A mulberry silk fill and a certified organic cotton shell. Both materials. No compromise. The fill: Grade 6A Mulberry Silk Grade 6A is the highest commercially graded mulberry silk assessed for fiber length,