Foam Vinyl Mat backing with resilient vinyl loops to which natural granite beach pebbles are adhered using a specially formulated polyurethane adhesive sealant by 3M. The adhesive is suitable for wet and dry applications. The beach pebbles are calibrated per color for the same gauge within 1/4" variance; diameter of pebbles ranges from 1" to 3" within 1/2" variance. There are varying gauges between the different pebble colors, most notably with white beach pebbles. Warranty Period: One year from date of purchase. Pebble Mat is NOT to be lifted by pebbles but rather vinyl backing. Pebble Mat is NOT suitable for vehicular traffic. Antimicrobial properties have not been determined by our company. Our mat backing is foam vinyl, which is a very common material used for upholstery in the marine industry and has excellent antibacterial properties. Any transformation to pebble mat, including cutting and application of adhesives not provided by Miami Beach Pebbles, Inc. will void all warranties. Installation: Pebble Mats should be installed atop of a pebble gravel bed or other nonangular gravel bed. For rooftop installations it is recommended that the Pebble Mat be installed atop of a Colbond brand polypropylene mat which raises the pebble mat allowing for proper drainage.