Screw-in anchors are designed for anchoring TallTowers in normal clay soils without many rocks. Screw-in anchors are installed by hand, using a cross bar to screw them into the earth like a corkscrew. Unlike a tent stake, screw-in anchors are installed at an angle so the eye of the anchor is toward the tower, and the 152mm (6\") helix screws in away from the tower. Made of galvanized steel, these anchors are corrosion resistant, easy to install, and will provide good holding power in a variety of soil types. Use these anchors with 30m - 50m TallTowers. Box of 4, cross bar not included. Reminder: NRG Systems offers its products exclusively to the wind energy industry. Anchors are sold for use with NRG Towers only.