It is possible to use fasteners for all standard grid types and all sub-constructions. Fasteners are specially designed for grilles used in walkable areas. Grilles used in areas that will be exposed to vehicle traffic can be supplied with perforated metal plates, which will optionally be welded between the carrier plates. In areas where there is a danger of falling, the grids must be connected at least from four corners. All fasteners require maintenance and their effectiveness must be checked regularly. Control intervals vary depending on operating conditions. The use and use of fasteners is the responsibility of the user. Therefore, all fasteners are outside the scope of legal warranty. The reference numbers of fasteners are determined by their pore openings and range from 20 to 66mm. The last two digits in the fastener reference numbers refer to the pore opening.