Our Zero Gravity Semi-Firm mattress is a true semi-firm mattress. The bottom of the mattress will feel strong and supportive. It's has our Zero Gravity Serene, Airflow foam as a transitional layer, and the top layer is comprised of a 1,5" soft 2.0lbs density foam. Perfect mattress for those looking for a strong, firm feeling support with a comfortable surface. This mattress is finished with our Bamboo breathable fabric.