These 3/16 in. x 2-3/4 in. Tapper flat head concrete screw anchors are sold as a box of 100. Tapper concrete screw anchors are manufactured for top performance in masonry-based applications and are designed to fasten objects into concrete, brick and block. The threads tap their own threads into the concrete, brick or block, and the line uses a Perma-Seal climate coating for long-lasting protection against corrosion. They are an excellent alternative to expansion anchors. For best results, use a hammer drill with a matching masonry bit.