The Colgate Foam Supreme II Crib Mattress is 5 inches thick and made with performance-tested CertiPUR-US® certified foam. It is firm like most medical experts recommend for babies, has a double layer, reinforced, tear-resistant, waterproof, easy-to-clean white cover. Like all Colgate crib mattresses, the Foam Supreme II is certified by GREENGUARD® to have no harmful air emissions and passes the tougher Children & Schools child products safety standard. It is safe from chemicals and compliant with the Consumer Product Safety Improvement Act (CPSIA). Flame protection is provided by a chemically-safe rayon cloth flammability barrier.