For attaching fastening clamps BSM or Bsmd in concrete without pre-drilling. Comes with Sze directly into the concrete tucked in setting toolures: durchmesser4,2 mmLÃ ¤ NGE18 Mmausfã forward Hrungeinschlagnagelkopfformsonstigewerkstoffstahloberflã at a Cheblau Angelassengehã degree of Rtetjaausfã 1/4 of Schraubnagelnein