Post anchor for square post is driven into the ground, creating a secure ground connection , and posts are attached using bolts & nuts. Additionally, it is performs as well as concrete in Independent testing, and keeps posts away from moisture, preventing rust & corrosion.It can Install in a variety of ground types include asphalt, dirt, sand, rocky ground, stones, etc. so that it is widely used in wood fencing, mail box, street signs, etc.
So it has a long life to reuse and provide cost effectiveness to you in the long run.
http://www.earth-anchoring.com