High-performance, dual density Rockdelta RB solution with a composite geotextile-geogrid. Dual density – high density top layer and low density bottom layer design – ensures that static and dynamic loads from gravel, stone, soil and other covering materials do not result in deterioration of the stone wool fibre material thus helping to provide the exceptional long product life cycle, e.g. as documented by the Technical University of Munich in approved test according to DIN 45673-5.