Wall-Dog Zip Screw. Used in wallboard, Brick*, Concrete*, Hollow or Grout filled Block* (*) Requires 3/16" pre-drill with masonry drill bit. Light Duty screw and anchor in-ONE. All steel, one piece, threaded anchorless screw. Use in Wallboard, Brick, Concrete, Hollow or Grout filled Block. No pre-drilling required when fastening into wallboard or wood.