These CRL Blue Plastic Anchors out perform most anchors, holding screws or nails in any drillable material. They are dependable, easy-to-use, and offer many advantages that assure better installations. These Anchors take a smaller hole, and the screw cuts its own perfect threads. They will not slip or turn as the screw is inserted, and are unaffected by corrosion, moisture or weather. You can use these PVC Anchors indoors or out. There are four standard sizes. Other sizes of Plastic Anchors are available on special order.