Screw-in anchors are the most commonly used anchors for normal clay soils without rocks. They are installed by hand, using a cross bar to screw them into the earth like a corkscrew. Screw-in anchors are the standard anchors supplied with NRG TallTowers. Screw-in anchors are also used to provide the anchoring rod and eye for site-built anchors, such as concrete. Features Simplest anchor to install. Versatile - good holding power in a range of soil types Reminder: NRG Systems offers its products exclusively to the wind energy industry. Anchors are sold for use with NRG Towers only.