Opera beds. Blending multi-layered springs with natural cotton and soft cashmere wool, the Natural 2500 provides sumptuous comfort for a great night�s sleep. Rated as a medium firmness, the mattress has a soft yet supportive filling inside. The two types of spring, pocket and micro-coils give you support and move with you as you reposition. The cashmere and wool blend gives softness, and the mattress is topped with a soft-touch tufted cover.