This ultimate comfortable self-filling mat is made of 50D stretch TPU. The mat has straight sides and is extra comfortable because of the unique 7 zones ergonomic pressure distribution. In addition, this SI mat is provided with a pleasant feeling elastic top layer which enhances the sleeping comfort. The top and bottom are also different in comfort. The hardness of the mat can be adjusted by blowing up or letting air escape. With double valve for quick inflation and draining, and supplied with carrying bag.