Hot Dip Galvanized (Complete with Rods) The malleable iron expanding rock anchor fits into a hole 1-7/8" or 2-3/8" in diameter, expands and wedges firmly against solid rock. When the anchor is expanded, the greater the pull on the rod, the harder the anchor becomes wedged. No lead, concrete or grouting equipment is necessary. Furnished complete with 3/4" and 1" rods, 15" to 8' in length. Anchors are painted black and the rods are hot dip galvanized.