Libra International Ltd offers Both Sides Usable Foam Mattress. Libra International Ltd is an ISO 9001- 2000 accredited company. The Both Sides Usable Foam Mattress is a light-weight, non-sagging combo-foam mattress that ensures the right balance of firmness and cushioning. The Mattress is available in the thickness of five inches and contains different layers of high density Polyurethane foam.