Guardian Fastening System is used as mechanical fastening of bitumen based multi layer or single ply roof coverings, or plastic based single ply roof coverings for flat roofing. The range of fasteners consists of washers, washers with integrated sleeve, screws, nails, and plugs as illustrated in Annex 1 in ETA 08/0285. Guardian Fastening System also consists of Centrix electro bonding system which is used to bond special adhesive coated metal fixing plates to single-ply waterproofing membranes.