not drywall. I can't drive the drywall anchors deep enough into the wall despite drilling a hole. (Pretty broken by the "putting in".) I ended up just pouring mastic or Locktite glue into the tube that came down the edges of this mop rack. The next day I hung up the mops/brooms/etc. anywhere and so far it's holding up well. I didn't have to stand and press the rack against the wall and wait 30 minutes for the glue to dry! I am very happy with the results.