Kährs Flex Silent is a permanently elastic underlay with a high water vapor diffusion resistance ( SD > 100 m), specially designed for floating installation of wood floors, offering a high class impact sound and walking noise reduction. It has excellent sustainability properties as it contains a minimum of 90% natural raw materials; minerals, castor and rapeseed oil and it can be reused with new floor coverings two or more times with near to 100% remaining performance.