Choosing between the auger and rock spike comes down to what's in the ground. Tony explains when to drill and remove material — limestone, papa, sandstone, and other sediment-based rock — versus when to spike and displace — river stone, shingle, asphalt, and gravel beds. The two kits are interchangeable with just two hinge pins to swap, and the telescopic mast provides over a tonne of down pressure on either. Most operators carry both, because ground conditions can change completely within a couple of kilometres.