Simpson 1/4 x 4 Mushroom Head Crimp Drive Anchor CD25400MThe Simpson Strong Tie Crimp Drive anchor is an easy to install expansion anchor for use in concrete and grout filled block. The pre formed curvature along the shaft creates an expansion mechanism that secures the anchor in place and eliminates the need for a secondary tightening procedure. This speeds up anchor installation and reduces the overall cost. The low profile mushroom head works excellent for attaching wood or light gauge steel to concrete