Package of 100 - 1/4 x 1 1/4 Zamac Hammer Screw, MushroomThe Zamac Hammer-Screw® is a unique, one-step drive anchor featuring a Phillips type head and a screw thread for use in concrete, block, brick or stone. With a body formed from corrosion resistant Zamac alloy and a carbon or stainless steel drive screw, this anchor has been developed by Powers as an improvement over standard nailin anchors.