EMAX smart alternating compressors are fully programable and paired together allowing the units to alternate from one unit to the another. In the case that one unit is not keeping up with demand, then both units will come on and run until the unit hits the pressure setting, after which it will go back into normal alternating mode. Built-in air demand sensor automatically increases or decreases the pump speed and air output based on actual air demand, reducing energy waste with fully programmable logic controllers it allows you to set the date, hours of operation, PSI and RPM ranges and digitally displays kW energy savings while the air compressor is running. Variable Speed Drive technology allows these smart air compressors to operate on single or three phase power options. Both units have our Patented pressure lubricated 2-stage cast iron pumps rated at up to 70,000 hours of use! Both units are equipped with our Whisper100 system lowing the DB levels up to 35%! Our aftercooler system cools the air going into the tank down to 10 degrees above ambient! This system helps combat moisture issues by cooling the air before it hits your lines helping protect your equipment With 84% energy savings on startups and 40% energy savings during run cycles, the silent air compressor will pay for itself in energy savings in 24 months!!