Simpson Strong Tie CSD25312 1/4" x 3-1/2" Counter Sunk Split Drive Anchor 100 per Box by Simpson Strong-Tie. $40.95. The Split Drive anchor is a one piece anchor, with a split type expansion mechanism on the working end. As the anchor is driven into the hole, the expansion mechanism compresses and exerts force against the walls of the hole. Can be installed in concrete, grout filled block and stone.