Microfibre Duvet Filling. Composition of filling: 100% hollow silicone fibre, Composition of cover: 100% polyester microfibre. Weight: 350 g/m² (250 g/m², in cot size). Medium warmth. Both the filling and the fabric are HYPOALLERGENIC but not DUST MITE PROOF. The hollow silicone fibre filling offers superior comfort and the cover has a pleasant peach fuzz feel. Machine washable up to 40ºC max. Do not tumble dry. 8 TOG.