Drop in anchor is composed of a cross cutting groove of anchor body and an inserted conical steel plug.During installing, to hit the conical steel plug with punching tool to expand the anchor body completely in the hole to generate expansion force and to fasten with bolt or stud.Used to anchor and fix the objects in the concrete,masonry,brickwork substrate.They are the internal threads concrete expansion anchors. The inch and metric sizes made with carton steel and stainless steel are available.