30 Double Disk Anchor, 34 Shaft, 30 Double, 4 Disk Earth Anchor With Double Fastening And Tensioning Head For Use With Straps. Designed To Be Augured Into Extremely Hard Soil Where 6 Anchors Will Not Suffice. Recommended For Soil Classes 2 and 3. Oliver Technologies Inc. Please Contact Your Local Building Inspector For Your Local Code On Anchors.