Froli sleep systems promote healthy sleep while saving an enormous amount of space and weight. By subsequently clipping in tension crosses, the degree of hardness can be increased in various areas if desired, e.g. for lumbar support. A standard mattress, preferably cold foam or latex, serves as the base. In a handy basic package, there is a complete kit for the standard dimensions of lying surfaces in touring vehicles. The Froli extension package adds missing elements in case of deviations from the standard dimensions. The systems can be clipped tightly or widely by selecting the hole spacing. Accordingly, the degree of firmness can be varied for the respective body weight.