ESSVE Indu-Prog concrete screws are used to fasten window and door boxes together with Indu-Prog box sleeve or Programa window sleeve. For quick and easy fixing in concrete, brick and hollow material. Can also be used for fastening to wood. Specially hardened screws that are screwed directly into the drilled hole, i.e. without a dowel. Full thread, i.e. "hi-low" thread for easy assembly. Screws made of hardened steel, bright galvanized. TX nozzle, TX30. If the mounting depth is increased, the load-bearing capacity improves. Concrete screws have been tested and approved for use in pulsating loads.