Trailer-mounted machine accepts power pack that lets operator use compressed air or high-pressure McLaughlin Group Inc., Greenville, S.C.to loosen soil and nondestructively expose utilities. Power pack fits manufacturer’s 500-, 800- or 1,200-gal. vacuum excavator. Combines 150-cfm rotary compressor with 3,000-psi water system. Three-stage filtration system allows for both wet and dry vacuum excavation. Allows water-based operation that digs quickly through challenging ground, as well as air-based excavation that keeps spoil dry for immediate return or reuse at site. Four-jet or nozzle-type digging tool directs water pressure to loosen soil and create a clean 6-in. hole. Runs on 85-hp turbocharged diesel engine. Options include hydraulic booms and sewer jetters.