The Blue Sovereign mattress is expertly designed, with a high individual pocket spring count and combination of cashmere wool and silk blend, it is the best mattress that performs in winter and summer, owing to its supreme temperature regulating properties, making it a cooling and warming mattress to ensure you have the perfect sleep. Silk fabric fibres are carefully blended with cashmere wool to form a durable insulation layer inside the mattress providing a cushioned supportive feel. Finished in a soft touch deep quilted cover offers enhanced comfort and edge to edge support. Somnior Beds Mattress Size: Small Double (4')