Foam N400 (hard) is one of the most reliable foams on the market. Foam N400 (hard) is ideal for you who are looking to replace the old foam in your sofa. The Afrolex N400 (hard) from Afrokoptiki is the best solution to strengthen the indoor or outdoor seat. Extremely durable, hard and reversible foam. It is also a foam recommended by doctors for sleeping on, so that there is anatomical direct support at the waist and spine.