This mattress is made of 35 % Foam + 65 % Polyester. It is composed of two parts that can be joined with two snap buttons. It has anti-skid underneath to avoid sliding on the seat and stretch bands to secure the front of the mattress to the sliding lid. It is machine washable 30°. It was released end of 2019 but is compatible with the BedBox bought before. We made it thinner and lighter to fit even more in the BedBox!