FROM THE MANUFACTURER:

The Spike is a, one-piece, vibration resistant anchor for use in concrete block or stone. Several head styles, including tamperproof versions, and anchor materials are available. The Spike anchor is formed with an �s� shaped configuration at the working end of the anchor to create an expansion mechanism. Since the anchor is pre-formed, there is no secondary tightening operation required which greatly reduces the overall cost of an anchor installation.