The frame is made of plywood of deciduous trees with a characteristic structure recommended for slats carrying heavy loads. It consists of 28 birch spring slats, the ends of which are mounted in flexible duoflex handles made of plastic resistant to cracking and deformation. The handles have additional cushioning, they are slid over the pegs embedded in the frame, which allows free tilting of the slat along the axis and exact adjustment to the anatomical shape of the body. Additional transverse lath connecting the frame in the central part. Transverse hardness adjustment on six slats in the lumbar region. Longitudinal tape strengthening bent strips. Recommended for all types of mattresses.