seismic exploration systems for hydraulic fracture treatment of subsurface formations and primarily composed of 100 lb. - 2450 lb. engine-driven hammers, and structural parts thereof in the nature of elastomer bands and piling hammers, earth and rock vibrators for seismic investigations, industrial power drills and drills accessories, namely, industrial drill rods and industrial drill heads for drilling into earth or rock, and each system sold as an independent unit or as a unit combined with...