Rock Shield Fleece 4 pipes
4 pipes GmbH . Sigmundstr. 182 . D-90431 Nürnberg . Phone +49 (0)911.81006-0 . Fax +49 (0)911.81006-111 . info@4pipes.de 
Documents to download:
This is a stapled-fiber-fleece-fabric made out of polypropylene. It protects pipes against mechanical stress, e.g. in stony grounds where a sufficient sand bedding is not available or possible. 
Product Datasheet