Screw-in anchors are designed for anchoring TallTowers in normal clay soils without many rocks. Screw-in anchors screw 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 helix screws in away from the tower. The 8 inch screw in anchors require a hydraulic drive for installation. This kit includes a pallet of 15, the appropriate number for installing a NRG XHD 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. Reminder: NRG Systems offers its products exclusively to the wind energy industry. Anchors are sold for use with NRG Towers only.