【Heavy Duty Durable Steel】- Our post anchor is made of ST12 cold-rolled steel plate, which is sturdy, durable, and corrosion-resistant, making them very strong and weather-resistant, you can insert the spikes into the ground easily and it will last many decades It can be used outdoors in damp wetlands for a long time and is durable 【Inner Diameter 3.6 "X3.6"】- Our post screw anchor is designed with an inner diameter of 3.6x3.6 inches, while also considering the use of 3.5x3.5 inches of wood, leaving some space. No dig ground anchor including 10 fixing screws and 20 inch long steel bars 【Protect Wood Post】- The heavy duty metal ground post anchor support the fence and mailbox posts without the need for holes to be dug or for concrete to be poured. With the wooden post being in contact with metal rather than soft (often wet) ground, your fence posts or mailbox will last considerably longer 【Easy to Install】- The No-Dig Ground Anchor offers a faster, cleaner, and easier way to install your posts. Just screw the item into the ground with the included rod. Only an initial press is needed for most soil types. And when the season is over, it can just as easily be screwed out again for other purpose 【Wide Applications】- This type of no dig ground anchor is widely used in farms, gardens, courtyards, road signs, fencing, wooden frames and mailboxes. NOT recommended for rocky or extremely sandy conditions 1