L.H Dottie 27600 Drop In Anchor 1/4"-20 Steel Zinc Plated is manufactured with an internally threaded, all-steel exterior shell that features an expansion cone insert used to anchor into the concrete. They are intended to be used in concrete materials only and can be used with any head style screw. The screw can easily be removed, loosened, or re-tightened if needed. Common applications include, pipe hanging, overhead anchoring, hanging strut, sprinkler systems and removable anchoring points.