Square Shaft (SS 150) Extension 48" long (1219 mm) w/ 14" (355 mm) Helix. Square Shaft Lead Sections are assembled to Square Shaft Extension with through bolt. The helical shaped plates do not auger into the soil but rather screw into it with minimal soil disturbance Hot dipped galvanized per ASTM A153. Capacity of anchor can be determined by measuring installation torque.